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    Identification, evolution and expression analysis of the CCoAOMT family genes in Medicago sativa
    Qian MA, Qi YAN, Zheng-she ZHANG, Fan WU, Ji-yu ZHANG
    Acta Prataculturae Sinica    2021, 30 (11): 144-156.   DOI: 10.11686/cyxb2020429
    Abstract803)   HTML39)    PDF (3463KB)(1428)       Save

    Alfalfa (Medicago sativa) is a forage legume with high feed quality widely cultivated all over the world. It contains lignins that play an important role in stress resistance of alfalfa. However, lignin seriously affects the nutritional value of alfalfa because it is difficult for livestock to digest. Therefore, it is necessary to breed alfalfa varieties with low lignin content. Caffeoyl CoA O-methyltransferase (CCoAOMT) is a key enzyme in the lignin synthesis pathway. In this study, the members of CCoAOMT gene family in the alfalfa genome were identified by bioinformatic methods, and the gene structure, chromosome location, phylogeny and gene expression were analysed. It was found that there were 44 MsCCoAOMT genes in the alfalfa genome. These genes were distributed on 16 chromosomes with tandem duplication, among which 36 (82%) MsCCoAOMT genes contained 5 exons. A phylogenetic tree was constructed and showed that MsCCoAOMT family genes can be classified into 5 groups. In addition, ten conserved motifs were found by predicting the motif of MsCCoAOMT protein with MEME software. qRT-PCR results indicated that most of MsCCoAOMT genes were tissue-specific in their expression. Our results provide reference information for the genetic improvement of alfalfa and development of lines with low lignin content.

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    Research progress on plant coumarin biosynthesis pathway and the genes encoding the key enzymes
    Zhen DUAN, Fan WU, Qi YAN, Ji-yu ZHANG
    Acta Prataculturae Sinica    2022, 31 (1): 217-228.   DOI: 10.11686/cyxb2020485
    Abstract1814)   HTML111)    PDF (967KB)(1389)       Save

    Coumarins, the important secondary metabolites of plants, derive from phenylpropanoids metabolism pathway, have a variety of biological activities and play an important role in plant growth and development and stress response. Here, the research progress of coumarin biosynthesis pathway and the genes encoding the key enzymes involved in coumarin biosynthesis were reviewed, and the phylogenetic evolution of the UDP-glucosyltransferase (UGT) gene family were analyzed. Moreover, the current research issues on coumarin biosynthesis were summarized and the future research directions were prospected in order to provide references for studying the coumarin biosynthesis and follow-up research.

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    Impacts of desertification and artificial revegetation on soil bacterial communities in alpine grassland
    Ya-ni WANG, Yi-gang HU, Zeng-ru WANG, Yi-kang LI, Zhen-hua ZHANG, Hua-kun ZHOU
    Acta Prataculturae Sinica    2022, 31 (5): 26-39.   DOI: 10.11686/cyxb2021120
    Abstract318)   HTML30)    PDF (4934KB)(880)       Save

    Characteristics of the soil microbial communities indicate the health of grasslands and quality of the environment. To elucidate the effects of desertification and artificial revegetation on the respective soil bacterial communities, four alpine grassland types including natural grassland (NG), desertified grassland (DG), grass-based artificial grassland (AG) and shrub-based artificial grassland (AS) in a small watershed of Guinan County, Qinghai Province were selected and qPCR and Illumina MiSeq high-throughput amplicon sequencing technologies were used to study the variation between the communities in bacterial biomass, diversity and structure. We also analyzed the key factors shaping soil bacterial community structure and their contributions based on variations in vegetation and soil properties. It was found that grassland desertification significantly reduced bacterial community biomass and α diversity (P<0.05), but that bacterial community biomass could be almost restored to the level of undegraded grassland after 22 years of artificial revegetation. Desertification significantly increased the relative abundance of Gemmatimonadota, while abundance of Proteobacteria and Planctomycetota significantly decreased (P<0.05). Artificial revegetation promoted the succession of dominant bacteria towards the community structure found in NG, and after 22 years of artificial revegetation, most of the bacterial relative abundances paralleled those of the undegraded status. Dissimilarity in bacterial community structure was noted between NG and DG, AG and AS, community structure in AG and AS were very similar. Soil bacterial community structure significantly positively correlated with the majority of vegetation and soil physiochemical properties (P<0.05). However, compared to soil physical (6.3%) and chemical (1.9%) properties, vegetation properties explained more variation (10.0%) in bacterial community structure. In total, the measured vegetation and soil indices explained 72.0% of variation in soil bacterial community structure, implying that vegetation and soil determine the shifts of soil bacterial community structure. Accordingly, it is essential and meaningful to strengthen vegetation and soil protection, and implement artificial revegetation in desertified grassland for protection and restoration of soil bacterial communities in Tibetan alpine grassland. However, the choice between shrub and grass planting during revegetation made little difference to the superficial soil bacterial community structure in artificial revegetation.

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    Screening and identification of two potassium solubilizer strains and their effects on the yield and quality of alfalfa
    Yan-jia WANG, Bo-ang HU, Jia-xin CHEN, Li-ting XU, Lin YAO, Li-rong FENG, Chang-hong GUO
    Acta Prataculturae Sinica    2023, 32 (12): 139-149.   DOI: 10.11686/cyxb2023036
    Abstract186)   HTML12)    PDF (2822KB)(826)       Save

    The study aimed to isolate and screen high-efficiency potassium solubilizing bacteria (KSB), and to quantify the effects of KSB application on plant yield and quality. The KSB strains were screened by silicate bacteria media from the rhizosphere soil of alfalfa (Medicago sativa), and subsequently the strains were identified by morphological, 16S rDNA sequence, and physiological and biochemical analysis. Pot experiments were conducted to evaluate the effect of inoculation with KSB strains on the yield and quality of alfalfa. Two high-efficiency KSB strains XLT-4 and XLT-7 were obtained with potassium solubilization rates of 10.53% and 9.75%>CK, and identified as Priestia megaterium and Peribacillus frigoritolerans, respectively. These two KSB strains had the metabolic capacity for phosphorus solubilization, siderophore-production and indole acetic acid secretion. Inoculation with XLT-4 and XLT-7 significantly increased plant height, root length, dry and fresh weight above ground and below ground, root activity, the contents of P, K and crude protein in leaves, while the contents of neutral detergent fiber and acid detergent fiber were significantly lower than in CK plants. In addition, the inoculation of the two KSB also improved the enzyme activity and available potassium content in alfalfa rhizosphere soil. In this study, the two KSB strains made a major contribution to improving the yield and quality of alfalfa, and these two organisms are high quality strain resources for the development of microbial preparations.

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    Advances and perspectives in forage oat breeding
    Xue-ling YE, Zhen GAN, Yan WAN, Da-bing XIANG, Xiao-yong WU, Qi WU, Chang-ying LIU, Yu FAN, Liang ZOU
    Acta Prataculturae Sinica    2023, 32 (2): 160-177.   DOI: 10.11686/cyxb2022263
    Abstract720)   HTML62)    PDF (857KB)(823)       Save

    Oat (Avena sativa) is an annual crop belonging to the Poaceae family with resistance to salinity, drought, cold stress, and adaptability to a wide range of environmental conditions including lower soil fertility. Oats are widely grown in temperate regions north of 40° N latitude in Europe, North America, and Asia. Oats also have a high forage yield, high nutritional value, good palatability, high digestibility, and the crop is suitable for silage and hay production. Therefore, oat is a versatile grain crop useful for food and forage purposes. Oat cultivars can be classified as naked or hulled oats depending on whether the grains readily separate from the husk or lemma at threshing. Hulled oats retain their husk. Naked oats without husks are mostly grown in China and are commonly used for food, while hulled oats which retain their husks are mainly grown in other countries, and are often used for feeding livestock. With the rapid development of animal husbandry in China in recent years, the available forage oat varieties are currently in need of improvement. Our country has formulated and implemented a series of policies that include “grass-based livestock husbandry”, “grain to forage” and “planting grass in fields”, which have promoted the rapid development of the forage oat industry. Under the strong support and guidance of these national policies and industry need, the planting area of forage oats has continued to expand, and the demand for new varieties has become increasingly urgent, which also points to higher requirements for the breeding of forage oats. In this study, we reviewed: 1) Collection, sorting, identification, and evaluation of germplasm resources of forage oats at home and abroad; 2) Four development stages of conventional breeding; and 3) The application of molecular technology in scientific research and breeding of oats. Based the above review, the current breeding objectives of forage oats are clarified, and the key points, difficulties, and immediate issues of forage oat breeding are discussed and analyzed, thus providing an important resource to underpin further developments in forage oat breeding.

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    Acta Prataculturae Sinica    2022, 31 (6): 1-10.   DOI: 10.11686/cyxb20220601
    Abstract724)   HTML70)    PDF (598KB)(720)       Save
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    Comparison of production performance and forage quality of ten introduced oat varieties in Hulunbuir, China
    Wei ZHANG, Qing-ping ZHOU, You-jun CHEN, Jing PAN, Xiao-ming JIN, Wan-bin SUN, Zhi-feng JIA
    Acta Prataculturae Sinica    2021, 30 (12): 129-142.   DOI: 10.11686/cyxb2021049
    Abstract588)   HTML13)    PDF (3466KB)(709)       Save

    In order to identify oat varieties best suited for cultivation in the Hulunbuir region, 10 oat varieties (Qingyan No.1, Qinghai No. 444, Jiayan No. 2, Qingyin No. 1, Linna, Qinghai sweet oat, Qingyin No. 2, Monica, Qingyou No. 3, and Fine horse) were trialed in the field and their forage and grain yields and nutritional composition were measured. Relative forage value and roughage grading index scores were used to evaluate and rank the forage quality and grey correlation analysis was used to derive a multivariate ranking of production performance. It was found that the time to maturity of the ten oat varieties ranged from 73 to 88 days. All matured early in Hulunbuir. Among the varieties, measured at the flowering stage, Qinghai No.444 was the tallest (113 cm, P<0.05), had the highest yield of fresh herbage (36620 kg·ha-1P<0.05), and had the highest hay yield (9990 kg·ha-1P<0.05). The growth time to maturity, plant height, leaf length, leaf width, plant diameter, and spike length was all significantly positively correlated with forage yield (P<0.01), while the leaf∶stem ratio and dry∶fresh weight ratio were extremely negatively correlated with forage yield (P<0.01). Qingyin No.1 had the highest grain yield (5439 kg·ha-1); this was not significantly different from Jiayan No. 2 (P>0.05), but was significantly higher than other varieties (P<0.05). Growth duration, plant height, stem diameter, spike length, round layers and thousand grain weight were all significantly positively correlated with grain yield (P<0.01), while spikelet number was negatively correlated with grain yield (P<0.01). With respect to forage quality, Qingyin No.1 had the highest ether extract content at the milk stage (P<0.05) and the highest crude protein and ash contents at the heading stage (P<0.05), while Qingyin No. 2 had the highest dry matter content at the heading stage (P<0.05). The multivariate analysis of production performance, nutritive value and forage value concluded that Qingyin No.1, Jiayan No.2 and Qinghai No.444 had superior production performance and higher nutritional quality and forage value, and can therefore be recommended for planting in the Hulunbuir region.

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    A taxonomic inventory of national key protected wild plants in Qinghai Province, based on the national checklist of key protected wild plants (2021)
    Jin-yuan CHEN, Wei-bo DU, Xu SU
    Acta Prataculturae Sinica    2022, 31 (9): 1-12.   DOI: 10.11686/cyxb2021502
    Abstract1051)   HTML37)    PDF (1244KB)(696)       Save

    Following the new national checklist of key protected wild plants, we made a taxonomic inventory of key nationally protected wild plants in the Qinghai Province. Data was drawn from consulting relevant literature and inspection of herbarium specimens. Our aim was to better understand their plant types, family and genus distribution, endemism, conservation status, and geographical distribution. It was found that: 1) Compared with species checklists in 1999, 44 key nationally protected wild species are newly added into the species list for Qinghai Province. 2) In Qinghai Province there are 53 species and one variety, 30 genera, 22 families and three categories of key nationally protected wild plants listed. Among them, Nostoc flagelliforme is a level-one key protected wild plant, and 52 species and one variety are level-two key protected wild plants. 3) The family with the largest number of plants listed is the Orchidaceae with 10 species, and the most commonly listed genus is Cypripedium containing eight species. 4) There is one genus endemic to China, there are three genera endemic to China and the Qinghai-Tibet Plateau (QTP), nine species endemic to China, nine species endemic to the QTP, 13 species endemic to China and the QTP and one species, Meconopsis barbiseta, endemic to Qinghai Province. 5) With respect to conservation status, there are 18 species listed as vulnerable (VU) level, and 12 species listed as endangered (EN) among the 54 key nationally protected wild species from Qinghai Province, which accounted for 55.55% of the total species. 6) Most of the key nationally protected wild species are distributed mainly in the alpine grassland and forest vegetation of Yushu and Golog Tibetan Autonomous Prefecture and Haidong city, which is consistent with the plant diversity distribution pattern in Qinghai Province. There are 53 species and one variety of key nationally protected wild plants in Qinghai Province, most of which are level-two key protected wild plants. Among these, 32 species are endemic species, accounting for 59.25% of the total, and 30 species are among the threatened species. Most of the key nationally protected wild plants are distributed in the southeast of Qinghai Province.

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    Progress of research on hormone regulation of branching or tillering in plants
    Fen-qi CHEN, Jin-qing ZHANG, Hui-ling MA
    Acta Prataculturae Sinica    2024, 33 (2): 212-225.   DOI: 10.11686/cyxb2023118
    Abstract335)   HTML27)    PDF (1243KB)(695)       Save

    Branching (or tillering in grasses and related taxa) is an important trait of plant architecture and the result of axillary bud initiation and growth, which plays a crucial role in determining the seed yield of crops and forage yield. Multiple hormones and their interactions play key regulatory roles in the occurrence, growth and development of plant branching or tillering. In addition, environmental factors also regulate branching or tillering by changing the hormone contents and their balances within the plant. This study reviews multiple aspects of the mechanisms by which plant branching or tillering is regulated various hormones, including auxin, cytokinin, strigolactones, brassinosteroids, abscisic acid and gibberellins, ethylene, jasmonic acid, and complex regulatory networks formed by the interaction of different hormone signals. The aim is to establish a foundation for using hormone regulation mechanisms to cultivate new high-yielding crop plant growth forms with ideal plant architecture. The current issues with hormone regulation mechanisms controlling plant branching or tillering are also analyzed, and future research directions for hormone regulation mechanisms controlling plant branching or tillering are discussed, with the aim of providing a theoretical basis for using hormones to cultivate good varieties.

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    Soil microbial biomass carbon and nitrogen levels and their controlling factors in alpine grassland, Qinghai-Tibet Plateau
    Yang LI, Yi WANG, Guo-dong HAN, Jian SUN, Ya-feng WANG
    Acta Prataculturae Sinica    2022, 31 (6): 50-60.   DOI: 10.11686/cyxb2021161
    Abstract618)   HTML31)    PDF (3105KB)(667)       Save

    The Qinghai-Tibet Plateau is an important geographically isolated and distinctive ecological zone in China. Soil microbes are important drivers of the biogeochemical cycle. Microorganisms are considered the core content of soil biochemical processes. Hence, exploring the content characteristics of soil microbial biomass carbon and nitrogen and their drivers is highly relevant to the understanding of ecosystem function. In this study, a field investigation is conducted in alpine meadows and steppes across the Qinghai-Tibet Plateau. Soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) levels were measured and their relationships with climate, plant community, and soil physicochemical properties were identified. It was found that MBC and MBN contents were higher in alpine meadows than those in alpine steppes. Furthermore, the growing season precipitation (GSP) showed significantly positive correlations with MBC and MBN in both alpine grassland types (P<0.01), while there were significant negative correlations between the growing season temperature (GST) and MBN in the alpine steppe (P<0.01). A structural equation model suggested that soil total nitrogen could mediate the MBC and MBN in the alpine meadow, and soil organic carbon may be the key factor of regulating MBC and MBN in the alpine steppe under the influence of growing season precipitation. The findings provide a theoretical framework for the sustainable management of these grassland ecosystems.

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    An evaluation of a remote sensing method based on optimized triangular vegetation index (TVI) for aboveground shrub biomass estimation in shrub-encroached grassland
    Zheng-yong XU, Bin SUN, Wang-fei ZHANG, Yi-fu LI, Zi-yu YAN, Wei YUE, Si-han TENG
    Acta Prataculturae Sinica    2023, 32 (10): 1-14.   DOI: 10.11686/cyxb2022488
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    Shrub-encroachment onto grassland is becoming an important ecological problem in grassland ecosystems, and accurate estimation of the shrub above-ground biomass (AGB) in shrub-encroached grassland vegetation plays a significant role in research into regional ecosystem carbon cycles. Due to the dual effects of soil background noise and differences in vegetation growth structure characteristics, the traditional vegetation indices are extremely unstable for model-building involving shrub-encroached grassland AGB estimation. To solve this problem, in this study we developed a novel way by optimizing the triangular vegetation index (TVI) using Sentinel-2 remote sensing data for shrub-encroached grassland AGB estimation. The results showed that: 1) In the area dominated by herbaceous vegetation, TVI calculated using a combination of green, red-edge and near-infrared ( R 560 R 705 and R 865 ) performed best with an R2 of 0.684; in the area dominated by shrub vegetation, the TVI again performed best with R2= 0.368. 2) When analyzing the sensitivity of the 12 commonly used vegetation indexes to soil noise, the enhanced vegetation index (EVI) was the most sensitive to soil noise in the area dominated by herbaceous vegetation; in the area dominated by shrub vegetation, the modified soil adjusted vegetation index (MSAVI) was the most sensitive. 3) In the area dominated by herbaceous vegetation, the optimized vegetation index grassland triangular vegetation index (GTVI) performed better than TVI with the value of R C V 2 (coefficient of determination cross validation) increased by 0.153 and the value of R M S E C V decreased by 12.222 g·m-2; in the area dominated by shrub vegetation, GTVI performed better than TVI and the R C V 2 value increased 0.029, while the R M S E C V (root mean square error cross validation) decreased 1.684 g·m-2. 4) The estimation results acquired by GTVI showed the highest accuracy when compared with the results estimated by the commonly used 12 vegetation indices. The results of this study are expected to provide a scientific basis and reference AGB estimation in shrub-encroached grassland using vegetation indices extracted from remote sensing data.

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    Research progress on the seed-shattering mechanism of Poaceae plants
    Wen-gang XIE, Yi-yang WAN, Zong-yu ZHANG, Jun-chao ZHANG
    Acta Prataculturae Sinica    2021, 30 (8): 186-198.   DOI: 10.11686/cyxb2020579
    Abstract535)   HTML40)    PDF (3464KB)(649)       Save

    Seed shattering is an adaptive characteristic of wild plants for effective reproduction and population expansion, but it adversely affects seed production. The formation, development, and degradation of the abscission zone are the direct causes of seed shattering in plants. Plant hormones produce signals that promote or inhibit seed shattering. Cell wall hydrolases can cause the degradation of cells in the abscission zone. The occurrence of these processes is regulated by polygenes and the regulatory network is complex. Research on seed shattering has been carried out in rice, wheat, and other crops, but comparatively few studies have focused on forage grasses. In this paper, we review the latest advances in research on seed shattering in poaceous plants to provide a theoretical reference for in-depth exploration of seed-shattering mechanisms and species selection.

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    Classification of Stellera chamaejasme communities and their relationships with environmental factors in degraded alpine meadow in the central Qilian Mountains, Qinghai Province
    Yong-mei LIU, Xing-zhi DONG, Yong-qing LONG, Zhi-mei ZHU, Lei WANG, Xing-hua GE, Fan ZHAO, Jing-zhong LI
    Acta Prataculturae Sinica    2022, 31 (4): 1-11.   DOI: 10.11686/cyxb2021310
    Abstract532)   HTML59)    PDF (1700KB)(628)       Save

    The invasion of Stellera chamaejasme has exerted an increasing impact on the alpine meadow ecosystem and animal husbandry on the Qinghai-Tibetan Plateau. In this study, we explored the relationships between S. chamaejasme communities and environmental factors on a local scale, using data for plant communities, soil characteristics, and topography collected from a typical degraded meadow in the central Qilian Mountains. The data were analyzed using two-way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA), and redundancy analysis (RDA). The main findings were as follows: 1) TWINSPAN divided the 45 plots into three association types: Association Ⅰ-S. chamaejasme+Stipa purpurea+Kobresia capillifolia+Thermopsis lanceolata; Association Ⅱ- S. chamaejasme+S. purpurea+Potentilla chinensis+Saussurea pulchra; and Association Ⅲ-S. purpurea+Anemone rivularis+S. chamaejasme+Poa annua. 2)The RDA analysis indicated that the distribution of S. chamaejasme was significantly affected by soil total phosphorus and soil total potassium content, followed by aspect. Soil nutrient contents played an important role in the spatial patterning of the three association types, and S. chamaejasme associations with high coverage were more susceptible to low-phosphorus and low-potassium conditions. 3)Species dominance in Associations Ⅲ, Ⅱ, and Ⅰ changed with the spread of S. chamaejasme, the importance values of the Poaceae forages P. annua and S. purpurea decreased (4.10, 3.12, 2.10), those of the Fabaceae species Gueldenstaedtia diversifolia and Medicago ruthenica initially increased and then decreased (0.28, 0.57, 0.25), those of the Cyperaceae species K. capillifolia and Kobresia humilis increased (0.23, 1.18, 2.19), and those of forbs and poisonous plants (S. chamaejasmeA. rivularis T. lanceolataAnaphalis lactea, and Morina kokonorica) markedly increased (6.10, 5.14, 10.08). Over time, S. chamaejasme replaced S. purpurea and became the dominant species in Associations Ⅰ and Ⅱ, and the S. chamaejasme coverage increased (5.5%, 11.0%, 29.7%). The results of this study reveal changes in the characteristics of plant communities in a degraded alpine meadow during S. chamaejasme invasion. These findings provide a scientific basis for the development of strategies to manage, restore, and develop the degraded alpine meadow and to effectively control S. chamaejasme.

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    The role of MAPK in plant response to abiotic stress
    Xin-miao ZHANG, Guo-qiang WU, Ming WEI
    Acta Prataculturae Sinica    2024, 33 (1): 182-197.   DOI: 10.11686/cyxb2023090
    Abstract648)   HTML42)    PDF (1316KB)(627)       Save

    Mitogen-activated protein kinase (MAPK) is a highly conserved serine/threonine (Ser/Thr) protein kinase, occurring widely in eukaryotic intermediate reaction pathways. Plant MAPK has 11 relatively conserved sub-domains, which are all essential elements for Ser/Thr protein kinase to play its catalytic role, and its expression is regulated by reactive oxygen species, nitric oxide and hormones. MAPK phosphorylates a variety of substrates including transcription factors, protein kinases and cytoskeleton related proteins, and plays an important role in regulating plant response to abiotic stresses (salt, drought, extreme temperature, and heavy metals). In this review, we summarize the results of research on the discovery of plant MAPK family members, their structure and classification, regulatory mechanisms, and their roles in response to various abiotic stresses. We also propose directions for future research. The information in this review provides a theoretical basis and identifies genetic resources for the genetic improvement of crops to produce new, stress-resistant varieties.

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    Progress in research on the photosynthetic characteristics of green non-leaf organs in plants
    Hui WANG, Hao-qi TIAN, Pei-sheng MAO, Wen-hui LIU, Zhi-feng JIA, Lu-ping WEI, Qing-ping ZHOU
    Acta Prataculturae Sinica    2021, 30 (10): 191-200.   DOI: 10.11686/cyxb2021117
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    Photosynthesis is one of the most important biochemical reactions in plants, and is a vital process for producing food and oxygen and purifying water resources for humans and animals. Efforts to improve photosynthesis in plants have traditionally focused on increasing photosynthesis in the leaves to increase yield. However, green non-leaf organs may also contribute to improving the overall photosynthetic capacity of plants. Compared with leaves, some non-leaf organs show a lower transpiration rate, higher water use efficiency, and stronger osmotic regulation ability under stress conditions, indicative of better stress resistance. Thus, non-leaf organs may make a considerable contribution to yield. In this paper, we review recent studies on photosynthesis in green non-leaf organs, including those on the photosynthetic performance of reproductive organs and stems, the methods used to evaluate the relative contribution rate, the influences of abiotic stress, the identification of photosynthetic pathways, and CO2 fixation in non-leaf green organs. We discuss the advantages and disadvantages of the methods used to evaluate the contributions of these organs to photosynthesis in the whole plant, and outline future directions for research on the photosynthetic ability of non-leaf organs.

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    Determination of the nutrient digestibility of herbage consumed by grazing animals
    You-shun JIN, Fu-jiang HOU
    Acta Prataculturae Sinica    2022, 31 (5): 200-212.   DOI: 10.11686/cyxb2021089
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    Nutrient digestibility of herbage consumed by grazing livestock is one of the key indicators for grassland management, and is a function of both the biomass and nutritional quality of forage, and the health and production status of livestock. Nutrient digestibility of forage consumed by grazing livestock can be determined by direct or indirect methods. The direct methods include, among others, the total feces collection method, the indigestible marker method and near infrared spectroscopy (NIRS). The indirect methods include in vivo or in vitro fermentation digestibility determinations, the forage quality prediction method and the climate prediction method. The total fecal collection method is a comparatively accurate method, provided that the feed dry matter intake and feces dry weight are accurately determined. However, it is time-consuming and laborious, and has a great impact on the grazing behavior. Moreover, it is difficult to reflect the spatial heterogeneity of forage supply in the pasture. The indigestible marker method estimates the nutrient digestibility according to the proportion of indigestible matter recovered and causes little disturbance to the grazing behavior of livestock. However, it is not easy to analyze for the indigestible marker, and the method is not suitable for wild grazing animals. The NIRS method has high efficiency, low labor intensity, low cost, and does not have any effects on livestock, so it can estimate the nutrient digestibility of forage consumed by grazing livestock on a large scale. However, NIRS requires a lot of directly measured calibration data to improve the prediction accuracy. The climate estimation method is fast, and therefore time-saving but is also less accurate. Climate estimation is therefore suitable for large spatial and temporal scales. The nutrient digestibility of forage consumed by grazing livestock is closely related to biological factors, environmental factors and social factors such as livestock class, grassland type, grazing methods employed, temperature and precipitation. Combined with remote sensing, unmanned aerial vehicle methods and artificial intelligence, the nutrient digestibility of forage consumed by grazing livestock can be accurately and quickly measured, providing support for grassland ecological restoration and livestock health and management.

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    Some scientific issues of forage breeding in China
    Zhi-peng LIU, Qiang ZHOU, Wen-xian LIU, Ji-yu ZHANG, Wen-gang XIE, Long-fa FANG, Yan-rong WANG, Zhi-biao NAN
    Acta Prataculturae Sinica    2021, 30 (12): 184-193.   DOI: 10.11686/cyxb2021314
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    New varieties of high yielding, high-quality and multi-resistance forages are the cornerstone of animal husbandry production in China, and also the material basis for reseeding and improving degraded grassland in China, both of which affect the food security and ecological security of the country. Slow progress of forage breeding in China and a high international dependence have emerged as a “bottleneck” restricting progress in the field of agriculture. In the last decade, forage breeding has entered a period of rapid development driven by histological techniques and biotechnology, but there is still a progress gap compared with major crops. This paper summarizes three key bottlenecks in the future development of forage breeding in China: 1) Large-scale collection, highly refined evaluation and full utilization of germplasm resources, including the construction of high-saturation mutant libraries, various genetic populations, and similar resources; 2) Establishment and optimization of efficient regeneration, genetic transformation and gene editing systems for forage grasses; 3) High-precision assembly and utilization of forage genomes, including gene chips, whole genome selection, and following developments in this field as they emerge. Considering current knowledge frontiers in the discipline and national needs, the authors suggest ten scientific emphases should be developed in forage breeding in China within the next 5-10 years: collection and utilization of native plant resources, threshing and dormancy, male sterility, ploidy breeding, biological interaction, water and drought conservation, domestication from scratch, nutritional quality, automated phenotype detection and rapid breeding, in order to provide a capability platform for future research related to forage breeding. Achievement of these scientific goals will help China to develop a number of new forage grass varieties with independent intellectual property rights and strong market competitiveness in a comparatively short time frame, so as to eliminate the “bottleneck” problem in the field of agriculture and guarantee the food security and ecological security of the country.

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    Progress in research and practice of restoration of degraded grassland around the world
    Li GAO, Yong DING
    Acta Prataculturae Sinica    2022, 31 (10): 189-205.   DOI: 10.11686/cyxb2022077
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    Grassland is one of the most important terrestrial ecosystems on earth, and brings humankind a series of ecosystem services, including food production, climate regulation, air purification, water conservation, wind prevention and sand fixation. Nearly half of the grasslands in the world are affected by climate change and human factors, and thus display different degrees of degradation. This degradation has become one of the world’s ecological and environmental problems. Much research on restoration of degraded grasslands has been carried out around the world with findings often leading to change in practice, and great progress has been made. However, at the beginning of the UN Decade on Ecosystem Restoration (2021-2030), a new generation of restoration research and practice projects is needed to cope with global environmental challenges. This paper summarizes the research and practice of degraded grassland restoration around the world, in the hope of learning from the existing grassland restoration work. On this basis, it is anticipated that we can map out the main direction of future research on degraded grassland restoration, and formulate reasonable restoration plans for degraded grassland, so as to provide reference information for new grassland restoration research and practice in the context of global change.

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    The grassland agriculture of Mongolia and its capacity to inform development in China
    Zhi-peng HUANG, Yi HUANG, Quan-jun YANG, Chao XIA, Yan ZHANG
    Acta Prataculturae Sinica    2023, 32 (6): 1-15.   DOI: 10.11686/cyxb2022265
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    Mongolia borders on northern China, has abundant grassland resources and grassland-based livestock husbandry is the pillar industry there. Based on the literature and statistical data, this study surveys the development status of grassland agriculture in Mongolia from three aspects: reform of the pastoral institutional system, the grassland resources, and the development of a grazing-based livestock industry. Our study also analyzes the differences between Mongolia and the Inner Mongolia Autonomous Region of China. Grassland agriculture in Mongolia has undergone three stages of institutional reforms, the post-transformation period began at 1990 and is ongoing till now. The grassland itself is collectively owned and the livestock is privately owned. Under the influences of climate change, over exploitation of grassland, expansion of cultivated land and urban areas, and mining pollution, the grassland area has decreased and the ecological status of the grassland is gradually deteriorating. The proportions for each of Mongolia’s five categories of livestock remain stable but with regional variability and differences. The growth in total livestock numbers is much higher in Mongolia than in Inner Mongolia, China. In recent years, the grazing-based livestock husbandry has faced a problem of an aging population. As a result, the proportion of animal husbandry output value within the national economy has gradually declined and the industrial chain urgently needs to be improved. Finally, this study proposes implications for Mongolia and offers information relevant to the development of grassland agriculture in China.

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    Research progress on rumen microorganisms in the utilization of lignocellulose as an energy resource
    Juan-shan ZHENG, KAO Ren-qing DING, Xin-pu LI, Ze-yi LIANG, Jian-bo ZHANG, Mei DU, Xue-zhi DING
    Acta Prataculturae Sinica    2021, 30 (9): 182-192.   DOI: 10.11686/cyxb2020316
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    The rumen is the first compartment of the digestive tract of ruminants, it functions as a pre-gastric anaerobic fermentation chamber, where are ingested plant material is degraded by various microorganisms (bacteria, fungi and protozoa) and converted into low-molecular-weight chemical compounds which are subsequently absorbed and digested by the animal. The rumen is currently recognized as a natural reactor, where a variety of lignocellulosic degrading enzymes are secreted by fungi and bacteria and the lignocellulose is degraded and utilized efficiently. Replication of rumen processes in vitro has potential value in the production of biofuels and chemical compounds from lignocellulose. Therefore, from the perspective of reviewing which rumen microorganisms degrade lignocellulose and related compounds, this paper focuses on the research progress of rumen microorganisms and organic acid biochemistry in the conversion of lignocellulose to ethanol and biogas. In compiling this overview, we aim to provide new methods and ideas for the research and application of rumen microorganisms in the utilization of lignocellulose as an energy or chemical synthesis resource.

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    Estimating grassland above ground biomass based on the STARFM algorithm and remote sensing data——A case study in the Sangke grassland in Xiahe County, Gansu Province
    Yu-zhuo ZHANG, Zhi-gui YANG, Hong-yan YU, Qiang ZHANG, Shu-xia YANG, Ting ZHAO, Hua-hua XU, Bao-ping MENG, Yan-yan LV
    Acta Prataculturae Sinica    2022, 31 (6): 23-34.   DOI: 10.11686/cyxb2021180
    Abstract527)   HTML244)    PDF (1697KB)(523)       Save

    Characteristics of remote sensing data include that they are real-time, dynamic and large-scale, so such data have been widely used in grassland resource monitoring and management research. However, a single remote sensing vegetation index can not meet the needs of temporal and spatial resolution in grassland above ground biomass (AGB) monitoring. Therefore, this study generated a high spatial and temporal resolution vegetation index data set based on a time series of Landsat NDVI and MODIS NDVI data, combined with the spatial and temporal adaptive reflectance fusion model (STARFM). The data set so generated (NDVISTARFM) had a temporal resolution 16 d and a spatial resolution 30 m. The optimum grassland above ground biomass inversion model was constructed based on measured grassland above ground biomass and NDVISTARFM during the grass growth seasons of 2013-2016. Finally, the spatiotemporal dynamic variation trends of grassland above ground biomass in the study area were analyzed for the period from 2000-2016. It was found that: 1) the optimal estimation model based on NDVISTARFM was a power model, with an R2 of 0.58 and an RMSE 795.62 kg·ha-1. The performance of this model was lower than that of the Landsat NDVI optimal estimation model (R2 =0.76, RMSE=634.83 kg·ha-1), but better than that of the MODIS NDVI optimal estimation model (R2 =0.24, RMSE=937.79 kg·ha-1). 2) The overall accuracy of the optimal estimation model was 84.05%, it was higher than that of MODIS NDVI but lower than that of Landsat NDVI. 3) The grassland above ground biomass showed an increasing trend in most areas from 2000-2016. About 90% of the study area showed an increasing trend with annual increment more than 30 kg·ha-1, while only 2.3% of the study area showed a decreasing trend.

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    Nitrogen fertilizer threshold and uncertainty analysis of typical grassland on the northern slopes of Tianshan Mountains
    Qi-fei HAN, Long YIN, Chao-fan LI, Run-gang ZHANG, Wen-biao WANG, Zheng-nan CUI
    Acta Prataculturae Sinica    2024, 33 (1): 19-32.   DOI: 10.11686/cyxb2023097
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    In the context of climate change and increasing human activities, a series of ecological problems have emerged in arid and semi-arid regions as one of the important and very vulnerable components of the terrestrial ecosystem. Exploring the impact of climate change and human activities on the net primary productivity (NPP) is of great significance for the rational use of natural resources and the sustainable development of agriculture and animal husbandry. Nitrogen fertilization is a way to promote increased NPP and appropriate fertilization can improve the NPP of grassland. To further explore the potential use of N fertilization, this study investigated four grassland types, alpine meadow (AM), mid-mountain forest meadow (MMFM), low mountain dry grassland (LMDG) and plain desert grassland (PDG), distributed along the altitude gradient on the northern slope of Tianshan Mountains, and employed a denitrification-decomposition model to analyze the NPP responses of the typical grassland ecosystem in this region to the application of different nitrogen fertilizers, and reveal the nitrogen fertilizer threshold and the optimal fertilization strategy. It was found that: 1) Appropriate nitrogen addition led to an increase in NPP of all types of grassland ecosystems, but there was a threshold value for the response of grassland NPP to fertilizer application, and different types of grassland NPP had different threshold values. There was no unified optimal fertilization method applicable to the four types of grassland. LMDG grassland ecosystem is the most sensitive to nitrogen application. 2) The maximum NPP in PDG grassland was achieved by applying 100 kg·ha-1 nitrate twice a year, and the maximum NPP was 68.72 g C·m-2·yr-1. The maximum NPP fertilization strategy in LMDG grassland is 260 kg·ha-1 of urea applied twice a year, and the maximum NPP value is 263.28 g C·m-2·yr-1. The maximum NPP of MMFM was achieved by applying 80 kg·ha-1 of urea once a year, and the maximum NPP is 171.22 g C·m-2·yr-1. In AM grassland, anhydrous ammonia reached the maximum value of NPP (114.62 g C·m-2·yr-1) with the minimum amount of fertilizer (60 kg·ha-1) and was the best nitrogen fertilizer in this grassland type. 3) The result of Monte Carlo uncertainty analysis shows that PDG and LMDG is more sensitive to fertilization time, and the effect of fluctuation in fertilizer application rate variation on LMDG and MMFM is more obvious.

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    Progress on the taxonomic classification of Medicago species
    Zhi-peng LIU, Guang-peng REN
    Acta Prataculturae Sinica    2022, 31 (11): 191-203.   DOI: 10.11686/cyxb2021426
    Abstract579)   HTML26)    PDF (736KB)(503)       Save

    This review investigates the disordered status of the classification of Medicago genus, both domestically and internationally. Several definitions of a taxonomic species were considered and the names and characteristics of 13 Medicago species in China are reported, together with a detailed summary of the names, life forms, chromosome numbers, pollination methods and natural distribution of about 90 Medicago species worldwide, including the classification of 14 sections and 10 subsections in Medicago. The molecular evolutionary relationships between different species, and the geographical origin of Medicago are discussed, and the genetic relationships between different subspecies in the alfalfa complex are further explained. This study puts forward a method of identifying Medicago species on the basis of deep understanding of the concept of species. A wide collection of global Medicago germplasm resources, aiming to further clarify the evolutionary relationship among different sections and different species by molecular evolution methods is proposed. This review provides a reference framework for future Medicago classification and alfalfa cross breeding.

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    Research progress on remote sensing discrimination techniques for grassland botanical species
    Meng-ge HUANG, Xin-hong WANG, Ling-ling MA, Xue-hua YE, Xiao-hua ZHU, Wei-ping KONG, Ning WANG, Qi WANG, Guang-zhou OUYANG, Qing-chuan ZHENG, Xiao-xin HOU, Ling-li TANG
    Acta Prataculturae Sinica    2023, 32 (6): 167-185.   DOI: 10.11686/cyxb2022278
    Abstract326)   HTML21)    PDF (1661KB)(502)       Save

    Grassland is an important resource bank for regional economic development and a crucial ecological reservoir for the security of China’s land-based ecological environment. Remote sensing technology is rapid, efficient, and low-cost, and therefore provides the mainstream technical means for large-scale grassland monitoring. The use of remote sensing technology to discriminate grassland species is an important way to monitor the population dynamics and botanical community succession in grassland. Such information is conducive to the timely and accurate detection of changes in the grassland ecological environment and provides an important reference for the scientific management of grassland ecosystems and the construction of an ecologically aware civilization. This study focuses on the problem of remote sensing discrimination of grassland species, clarifies the technical process of grassland species discrimination and introduces the latest research progress. Technical difficulties are covered from three perspectives: The characteristics of the main remote sensing data sources for grassland species discrimination and their acquisition techniques, important grassland species discrimination features and their mining techniques and the current commonly used grassland species discrimination methods and models. This study concludes that hyperspectral and LiDAR remote sensing and their fusion technologies have application prospects in the remote sensing discrimination of grassland species, and that the deep mining of multidimensional features and the effective combination of complementary features can improve the accuracy of grassland species discrimination. This study identifies the main problems of the current remote sensing discrimination technology for grassland species, and opens the prospect of the future precise discrimination of grassland species through remote sensing technology and thereby provides a theoretical reference for a thorough understanding of the field of remote sensing identification of grassland species and in-depth research on grassland species discrimination.

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    Effects of different additives on fermentation quality and protein degradation of Broussonetia papyrifera silage
    Chang-rong WU, Sheng DAI, Long-fei LIANG, Wen-tao SUN, Chao PENG, Chao CHEN, Jun HAO
    Acta Prataculturae Sinica    2021, 30 (10): 169-179.   DOI: 10.11686/cyxb2020379
    Abstract368)   HTML11)    PDF (1690KB)(498)       Save

    The study evaluated the effects of different additives on nutritive value, fermentation quality, nitrogen components and protease of Broussonetia papyrifera silage. Molasses was added to B. papyrifera after 1.5 h drying in the air as a control treatment (CK). In the additive treatments, formic acid (FA), cellulase (CE) or lactic acid bacteria (LB) were added to the B. papyrifera with molasses, with 3 replicates of each treatment. The changes in nitrogen components and enzyme activity were measured at 0, 3, 7, 15, 30 and 45 days of ensiling, and nutritional quality and fermentation quality were measured after 45 days. Results showed that contents of dry matter, crude protein, lactic acid and acetic acid were increased, while crude fiber, neutral detergent fiber, acid detergent fiber, propionic acid content, pH and ammonia nitrogen/total nitrogen were decreased (P<0.05) in FA, LB and CE treatments relative to CK. pH value, total nitrogen content, activities of acid protease, carboxypeptidase and aminopeptidase decreased with increase in time ensiled, while non-protein nitrogen, ammonia nitrogen and free amino acids gradually increased as fermentation progressed, and these indexes mentioned above in FA, LB and CE treatments were lower than in the CK treatment at each sampling time (P<0.05). The contents of peptide-N in FA, LB and CE groups were higher than in the CK treatment at each sampling time. As ascertained by membership function analysis, the overall nutritional value of B. papyrifera silage treated with different additives, ranked from high to low was: LB>CE>FA>CK.

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    Effects of Epichloë endophytic fungi on the germination of grass seeds
    Chun-jie LI, Ming-xiao LANG, Zhen-jiang CHEN, Tai-xiang CHEN, Jing LIU, Yuan-yuan JIN, Xue-kai WEI
    Acta Prataculturae Sinica    2022, 31 (3): 192-206.   DOI: 10.11686/cyxb2020601
    Abstract398)   HTML21)    PDF (778KB)(494)       Save

    Seeds are the most basic output generated in agricultural production, and seed germination plays a decisive role in survival and reproduction of species. However, the process of germination is easily affected by various environment factors. It is significant to improve germination quality in stress condition for grass planting. The establishment of the symbiotic relationship in plants with Epichlo? endophyte confers on the symbiosis higher germination rate, stronger resistance to adverse stress, and leads to the occupation of a more favourable ecological niche in the phytocoenosis. Hence, the Epichlo? endophyte has a wide impact in ecosystems, with ramifications affecting animals, plants and microorganisms within an ecosystem. This study reviewed the influence of Epichlo? endophyte infection on host grass germination under different habitats and treatments, with a focus on roles of endophyte in seed germination under natural growth conditions and various stress conditions, including allelopathy. It was found that endophyte promotes seed germination under both natural and stress conditions. However, germination responses were inconsistent in the presence of allelopathic effects. Additionally, the negative effect on germination caused by extended storage time is alleviated by endophyte infection. Building on previous research, we should prioritize research into the physiology and biochemistry of promoting germination and enhancing resistance to biotic and abiotic stresses in grass infected with Epichlo? endophyte, and on defining the mechanism whereby endophyte fungi influence germination, in order to identify excellent endophytic strains and explore novel ways of creating grass germplasm resources using Epichlo? endophyte.

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    Research progress on effects of nitrogen deposition on soil nitrogen cycling in grassland ecosystems
    Jiao-yun LU, He-shan ZHANG, Hong TIAN, Jun-bo XIONG, Yang LIU
    Acta Prataculturae Sinica    2022, 31 (6): 221-234.   DOI: 10.11686/cyxb2021156
    Abstract584)   HTML42)    PDF (780KB)(488)       Save

    The intensification of human activities and the use of fossil fuels has increased atmospheric nitrogen deposition, which has a significant impact on the nitrogen cycling processes of terrestrial ecosystems, thus affecting ecosystem productivity and stability. Grasslands, are an important component of terrestrial ecosystems, and in many cases are subject to resource loss and nutrient imbalance due to human overuse and lack of awareness of protection needs, in which case the development of animal husbandry enterprises can be severely limited. It is highly relevant to explore the influence of nitrogen deposition on nitrogen cycles of grassland ecosystems for rational development of policy and practice with respect to utilization of grassland resources. This paper tracks published research results at home and abroad and a key finding is that most nitrogen addition inhibits biological nitrogen fixation processes, promotes nitrification, denitrification and mineralization in soils, inhibits the activity of nitrogen fixing microorganisms, and increases the abundance of ammonia-oxidizing bacteria of nitrifying microorganisms and expression of functional genes of denitrifying microorganisms, such as nirKnirSnirG and nosZ. However, the responses of the soil nitrogen cycle to nitrogen deposition in a few studies differed from the above due to differences in nitrogen nutrition and nitrogen application measures in a grassland environment. Through summarizing the existing studies, we found that: 1) The effects of nitrogen deposition on the nitrogen cycle differ between studies due to different soil background nutrient levels and nitrogen absorption thresholds; 2) Microorganisms are important participants in the soil nitrogen cycle, and the responses of microorganisms to nitrogen addition differ with different nitrogen application time, frequency and quantity. 3) The various steps of the nitrogen cycle in soils are closely coupled and influence each other, but most of the existing studies only focus on a particular step, and therefore the results do not provide comprehensive insight. Therefore, in future studies, it will be necessary to pay more attention to the study of soil nitrogen cycle microbial changes under particular nitrogen supply conditions in grasslands with different nutrient levels, and consider the multi-step coupling relationship, which is very important to the improvement of grassland ecosystem function and reduction of the threat caused by nitrogen loss from the environment.

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    Precision grazing management of grassland: Concept, theory, technology and paradigm
    De-li WANG, Ling WANG, Guo-dong HAN
    Acta Prataculturae Sinica    2022, 31 (12): 191-199.   DOI: 10.11686/cyxb2022047
    Abstract467)   HTML22)    PDF (1865KB)(468)       Save

    With the development of human understanding of the multi-functionality of grassland, coupled with the increasing demand for grassland ecological services, animal production and pastoral living, it is necessary to update the concept of grassland management, develop higher level livestock grazing and feeding technology based on multidisciplinary theories, and establish a more effective grassland grazing management paradigm. This study considers both the background and characteristics of the grassland resources and modern multi-dimensional social demands, and develops the concept of precise grassland grazing management which encompasses the versatility and stability of the grassland ecosystem and sustainability as the goal and the use of grassland science, animal science, ecology and other multi-disciplinary theories, based on the habitat conditions, especially the vegetation characteristics, livestock classes and their requirements, and livestock-vegetation interactions. Through multi-dimensional, effective and directional regulation of the livestock grazing process, the grassland management and utilization paradigm of synergistic balance between production and ecological functions can be finally realized. Also, the concepts and connotations of precise grazing and its relevant theoretical bases are systematically explained, including the plant compensatory growth mechanism, the intermediate disturbance hypothesis, the theory of diversifying grazing livestock, mechanisms of plant-animal interactions, nutrition regulation principles and versatility synergy. These concepts form a scientific basis for the regulation of grazing pressure and livestock assembly. In conjunction with this coverage, the key points in precision grazing are reviewed, such as dynamic optimal stocking rate (threshold), mixed grazing (species and proportion), remote sensing information options (satellite, unmanned aerial vehicle monitoring, large scale data processing) and other related supporting technologies. Finally, the authors sum up the concept of grassland multifunctionality as a goal of “combining productive function and ecological service in a win-win manner”, so providing a precise grazing management paradigm. This approach provides a principle for the integration of natural grassland grazing, grassland grazing with supplementary feeding, and drylot feeding, reflecting region-wide whole industry regulation of livestock grazing pressure/assembly and provision for animal nutrition, while aiming for grassland grazing systems to achieve an overall “livestock-vegetation balance”. Such a system will generate high quality animal products and sustainable ecological services. Precise grazing management of grassland is advanced, practical and extensive, and therefore is a desirable choice for future grassland management with great potential and prospect.

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    Spring phenological characteristics of dandelion and plantain in Shandong Province and their responses to climate change
    Wen-hui GUO, Run-yuan GU, Feng DING
    Acta Prataculturae Sinica    2021, 30 (12): 27-38.   DOI: 10.11686/cyxb2020471
    Abstract366)   HTML22)    PDF (4152KB)(464)       Save

    This study utilized data from phenological observations of dandelion and plantain in Shandong Province from 2000 to 2015 and meteorological data for the same period, to discern factors influencing the phenological variation in spring development of these two plant species. Analytical methods employed included an empirical orthogonal function (EOF), Pearson correlation and partial least squares regression (PLS). It was found that: 1) From 2000 to 2015, dandelion and plantain showed a tendency to delayed germination and leaf expansion, which was more obvious in coastal areas. Seasonal timing of florescence was also linked to interannual climate variation at specific sites. 2) Increase in average temperature in winter and February significantly promoted the germination and leaf expansion of the two plant species. Germination, leaf expansion, and early florescence showed a significant negative correlation with cumulative precipitation in January, and germination and leaf expansion also showed a significant negative correlation with sunshine duration in winter. Beside the heat accumulation in winter, the average temperature and active accumulated temperature in March was positively correlated with the early florescence, the influence was gradually stronger from eastern to western Shandong, especially for plantain. 3) Fitted results of the PLS regression model for phenology of dandelion and plantain showed that: the ‘variable importance of projection’ (VIP) values of the average temperature in February, the average temperature in winter, the average surface soil temperature at 0 cm in winter, and positive accumulated temperature in winter were all greater than 1 in the early period of germination and leaf expansion. The VIP values of the average temperature and accumulated growing degree days in March, the average temperature in winter and the average soil surface temperature in winter were all greater than 1 in the early florescence.

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    A bibliometric evaluation of the status of the water conservation function of grassland ecosystems
    Xiao-ning ZHANG, Xiao-dan LI, Li-li NIAN, Ying-bo YANG, Xue-lu LIU
    Acta Prataculturae Sinica    2022, 31 (6): 35-49.   DOI: 10.11686/cyxb2021160
    Abstract356)   HTML32)    PDF (4129KB)(463)       Save

    Grassland ecosystems are the largest ecosystem category of the terrestrial surface. Changes in grassland water conservation function are an important indicator of ecosystem condition, and respond to regional water cycles and global climate change. Using the Web of Science core collection and the China Knowledge Network database, the knowledge structure of water conservation research in grassland ecosystems was mapped using the visualization software packages VOSviewer and CiteSpace and bibliometric summaries of the relevant literature were compiled. It was found that there was a growing awareness of the field globally, with a fluctuating upward trend in the number of publications. The countries producing the highest numbers of studies were China and the United States, and the top three research institutions were all Chinese institutions; namely the Chinese Academy of Sciences, the University of the Chinese Academy of Sciences, and Beijing Normal University. Core author groups for this literature exhibited a pattern of “large dispersion and small aggregation” with the core authors as the nodes of research and little cooperation among research groups. Major publications included Science of The Total Environment, Catena, Agriculture Ecosystems & Environment, Journal of Ecology and Journal of Soil and Water Conservation. The keywords ecosystem services, land use change, soil moisture, soil physical and chemical properties, and InVEST model were the most frequently mentioned topics of research in this field, both in China and abroad, in recent years. Soil moisture-soil physicochemical properties, combined with remote sensing technology to construct spatial and temporal scale evaluation models have become the frontier of research in this field. This study seeks to understand the current international research frontiers, clarify the developing trends in this field and summarize the research themes in order to promote further development of water conservation research in grassland ecosystems.

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    A transcriptomic study of physiological responses to drought and salt stress in sweet sorghum seedlings
    Zhi-heng WANG, Yu-qing WEI, Yan-rong ZHAO, Yue-juan WANG
    Acta Prataculturae Sinica    2022, 31 (3): 71-84.   DOI: 10.11686/cyxb2020557
    Abstract430)   HTML29)    PDF (9009KB)(450)       Save

    This research aimed to explore the molecular mechanisms, metabolic pathways and physiological differences of responses to drought and salt stress in sweet sorghum, in order to strengthen the scientific information available to enhance sweet sorghum forage crop husbandry and breeding. Seedlings of sweet sorghum cultivar Liaotian No.1 were used to provide the plant material for study. Moderate drought stress was induced using 10% PEG-6000 solution and salt stress was simulated using 0.9% NaCl solution. Photosynthetic gas exchange parameters, endogenous hormone content, content of organic osmotic regulatory substances and antioxidant enzyme activities were determined on days 2 and 7 of stress exposure. Concurrently, transcriptome sequencing and bioinformatics analyses were carried out on seedling leaves, and qRT-PCR was used to verify the sequencing results. For sweet sorghum seedlings under salt stress, photosynthetic parameters, endogenous auxin concentration and degree of cytokinin inhibition were higher than under drought stress; Soluble sugar content was significantly higher under drought stress than under salt stress; Antioxidant enzyme activities and abscisic acid concentrations were higher under salt stress than under drought stress, indicating different physiological mechanisms of drought and salt stress response in sweet sorghum. Under drought stress on day 2, transcriptome sequencing identified 922 up-regulated and 975 down-regulated genes while under salt stress there were 2047 up-regulated and 1714 down-regulated genes. At day 7 under drought stress there were 157 up-regulated and 54 down-regulated genes while under salt stress there were 795 up-regulated and 722 down-regulated genes. Forty drought stress response genes and 493 salt stress response genes were also identified. Gene ontology (GO)-based enrichment analysis revealed that sweet sorghum seedlings under drought and salt stress were significantly enriched in pathways involving plant response to stress. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that genes up-regulated in response to drought stress tended to be involved in endoplasmic reticulum processing and shear body metabolism pathways, while salt stress response genes were generally associated with plant hormone signal transduction metabolic pathways. Analysis of the genes related to photosynthesis, plant hormone signal transduction, antioxidant enzymes and starch and sucrose metabolic pathways showed that the expression patterns of these genes were consistent with the observed changes in physiological indicators. Therefore, sweet sorghum adaptation to salt stress lags behind response drought stress at the transcriptional level. Meanwhile, the tolerance of sweet sorghum seedlings to moderate salt stress was lower than that under moderate drought stress. Soluble sugars played an important role in the resistance to drought stress of sweet sorghum seedlings. The joint regulation of plant hormone signal transduction and antioxidant enzyme activity changes was the key to the resistance of sweet sorghum seedlings to salt stress.

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    Research progress on vigor estimation for forage seeds
    Qi-bo TAO, Xi-hu QIE, Qian ZHANG, Yu-xuan GAO, Ya-qi ZHANG, Rui-zhen ZHANG, Xiao-fei CHEN, Tian-xiu NIU, Xiao-tong SUN, Yu-ting NIE, Ya-ru LIU, Jia-qi HU, Shang-zhi ZHONG, Juan SUN
    Acta Prataculturae Sinica    2023, 32 (10): 200-225.   DOI: 10.11686/cyxb2023007
    Abstract227)   HTML12)    PDF (827KB)(445)       Save

    High-quality forage seeds are fundamental materials for grass-husbandry industry development and ecological restoration in China. Seed vigor is an important aspect of evaluate seed quality. The efficient vigor estimation of forage seeds is of great importance for selection of high-quality seed lots for cultivated grassland establishment and improvement of natural grassland, and is therefore critical to ensuring food and ecological security. Numerous studies on diverse forage seed vigor estimation methods and their ability to predict field performance have been carried out and published. In this study, the concepts and methodologies for forage seed vigor estimation are summarized, with particular emphasis on the estimation principles and their application in forage seed vigor estimation of some of the more commonly used methods. Coverage of this review includes forage seed physical properties, germination and seedling growth characteristics, stress testing, physiological and biochemical indicators, and advanced technologies. Future prospects in this field are also identified and discussed, to provide necessary direction for the improvement of future research.

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    Change in grassland productivity in Qinghai Province and its driving factors
    Ya-hui WANG, Wen-jia TANG, Sen LI, Hong-yan ZHAO, Jia-li XIE, Chao MA, Chang-zhen YAN
    Acta Prataculturae Sinica    2022, 31 (2): 1-13.   DOI: 10.11686/cyxb2021256
    Abstract524)   HTML97)    PDF (6577KB)(443)       Save

    In recent years, grassland in Qinghai province has been affected by climate change and variously impacted by a range of human activities, sometimes causing degradation and sometimes facilitating restoration. Here we report a survey of the spatial and temporal variation in grassland productivity across Qinghai Province for the period from 2001-2017. To extract data on grassland net primary productivity (NPP, MOD17A3HGF.006), Sen’s slope together with the Mann-Kendall test (Sen-MK), correlation analysis and residual analysis were used as decision nodes of a decision tree. Then we used the tree to evaluate grassland NPP time trends and their spatial heterogeneity during the study period and identify associated factors that may be change drivers. The results were as follows: 1) There were 11.41×104 km2 of grassland with significant (P<0.05) NPP trends in Qinghai Province during the 2001-2017 period. The areas of extremely significant (P<0.01) increase, significant (0.01≤P<0.05) increase, significant decrease and extremely significant decrease were respectively 11.88%, 17.25%, 0.20% and 0.08% of the grassland in the province. Remarkably, the overall change is a rise in NPP. 2) For the regions where grassland NPP trends were significant, the proportion explained by temperature was the largest (60.66%), followed by human activities (23.45%) and human activities + temperature (9.49%). Hence, temperature and human activities were the major factors driving significant grassland NPP trends. 3) Temperature, precipitation and human activities mainly had positive impacts on NPP. Human activities were the dominant factor linked with grassland degradation and were associated with 77.49% of the grassland area with a decreasing NPP trend. However, human activities have also achieved remarkable results in grassland restoration and ecological protection projects in Qinghai Province.

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    Research status and suggestions for grassland carbon sequestration and emission reduction in China
    Zi-jing LI, Cui-ping GAO, Zhong-wu WANG, Guo-dong HAN
    Acta Prataculturae Sinica    2023, 32 (2): 191-200.   DOI: 10.11686/cyxb2022049
    Abstract451)   HTML34)    PDF (715KB)(440)       Save

    With rapid economic development, and continuing increase in the emission of greenhouse gases, coupled with intensification of human use of natural resources, the carbon sequestration capacity of the global ecosystem has weakened, and the concentration of greenhouse gases in the global atmosphere has reached a new high. This has become a major global issue of general concern to the international community. China’s grassland carbon sink resources are unique, and the development of the grassland carbon sink economy has become an important vehicle for fulfilling international commitments, creating a new carbon sequestration economy and building a beautiful China with regenerative food production systems. This study reviews the current status of grassland carbon sequestration and emission reduction in China and the factors influencing sequestration, including research into grassland carbon sink capacity and reduction of emissions linked to livestock production now that there is a background of climate change and establishment of sown artificial grassland construction. Our review proposes a plan for the development of grassland carbon sequestration and emission reduction in China and provides a theoretical basis for contribution to carbon neutrality, and carbon sequestration and emission reduction in China’s grasslands.

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    The use of the tRNA-sgRNA/Cas9 system for gene editing in perennial ryegrass protoplasts
    Jia-ming YAO, Huan-huan HAO, Jing ZHANG, Bin XU
    Acta Prataculturae Sinica    2023, 32 (4): 129-141.   DOI: 10.11686/cyxb2022180
    Abstract560)   HTML35)    PDF (3944KB)(436)       Save

    Transfer RNA (tRNA) can link multiple sgRNAs (single-guide RNAs) to form a polycistronic gene, which then combines with a CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated gene 9) expression vector to form a polycistronic tRNA-sgRNA/Cas9 (PTG/Cas9) system for multiple gene editing. The PTG/Cas9 system has been used to alter sgRNAs transcript levels and improve multi-target editing efficiency in rice (Oryza sativa). To efficiently edit target genes in perennial ryegrass (Lolium perenne), we generated two CRISPR intermediate vectors with tRNAs to provide a fast and flexible PTG/Cas9 vector construction method. To verify whether the PTG/Cas9 system effectively edits genes in the perennial ryegrass genome, we introduced the PTG/Cas9 plasmid into perennial ryegrass protoplasts by PEG 4000-mediated transformation. Then, we extracted DNA from protoplasts and amplified the target sequences to determine whether they had been edited successfully. The gene editing efficiency was about 6.7%. These results show that the PTG/Cas9 system can be used for gene editing in the ryegrass genome, and provide the basis for further genetic research on, and breeding of perennial ryegrass.

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    Ecological value and its spatiotemporal dynamic patterns of grassland in China
    Jia-hui LI, Lin HUANG, Jiang-wen FAN
    Acta Prataculturae Sinica    2023, 32 (12): 1-13.   DOI: 10.11686/cyxb2023058
    Abstract290)   HTML70)    PDF (5832KB)(435)       Save

    As China’s largest terrestrial ecosystem and one of the important natural resources, grasslands provide a series of ecosystem services which contribute to human well-being. However, there are still wide expanses of grassland suffering from various degrees of degradation, and requiring urgent conservation and restoration action to improve their quality, function and stability. Accounting of grassland ecological value provides an effective means to monitor the changes in and assess the combined importance of multiple grassland ecosystem functions. This study analyzed the spatiotemporal evolution of grassland ecological value in China from 2000 to 2020. It then assessed the spatiotemporal dynamics of the value of key ecological services of grasslands, including windbreak and sand fixation, water conservation, forage supply and carbon sequestration. Next, adaptation strategies for optimizing and enhancing the grassland ecological value in China were proposed. It was found that in 2020, the ecological value of China’s grassland was 2.47×104 billion CNY, and the value was 7.6 million CNY·km-2, among which the value per unit area of windbreak and sand fixation and species richness maintenance were relatively high, accounting for 27.3% and 25.8% of the total, respectively. In the past 20 years, more than 90% of China’s grassland area has shown an increasing trend in ecological value. This applies especially to grassland located on the eastern Qinghai-Tibetan Plateau, the northern Loess Plateau, and the eastern and central parts of Inner Mongolia indicate a rapid growth. Moreover, the sum of grassland ecological values of Mongolia, Tibet, Qinghai, Sichuan and Xinjiang accounted for about 67.4% of China’s total ecological value. In the past 20 years, Shaanxi, Beijing, Ningxia, Tianjin, and Shanxi showed a relatively high growth rate in grassland ecological value (>65%). Finally, China’s grasslands were divided into three categories and twelve subcategories, based on grassland protection and restoration strategies focusing on different key ecological services. Our study offers significant insights for assigning various protection and restoration priorities to achieve sustainable growth in grassland ecological value.

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    A study of yield interactions in mixed sowings of alfalfa and three perennial grasses
    Hui-hui ZHANG, Shang-li SHI, Bei WU, Zi-li LI, Xiao-long LI
    Acta Prataculturae Sinica    2022, 31 (2): 159-170.   DOI: 10.11686/cyxb2021175
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    This study investigated the yield and competitive interactions in three mixed-sown combinations of alfalfa (Medicago sativa) and a perennial grass (M. sativa+Poa pratensisM. sativa+Bromus inermis and M. sativa+Festuca arundinacea). The mixtures were established at legume∶grass ratios of 7∶3, 5∶5, and 3∶7, and monocultures of alfalfa and the three grasses were also included as a contrast. Data on biomass and key morphological traits of each species in the various monocultures and mixed sowings were collated and analyzed to investigate the competitive interactions between alfalfa and the three grass species, so as to provide a theoretical basis for the development of management guidelines for high yield and high quality of mixed sown pasture. Results indicated that the relative yield (RY) values of alfalfa in the three mixed sowing combinations were higher than 1.0 and that alfalfa had a competitive advantage over the grasses. The growth of the grass in the combinations of M. sativa+P. pratensis and M. sativa+B. inermis was suppressed by alfalfa, while grass in M. sativa+F. arundinacea combination grew synergistically with alfalfa. For the three legume∶grass ratios tested in the mixed-sown plots, the RY for the alfalfa component ranked 3∶7>5∶5>7∶3 and RY for the grass component ranked 3∶7>7∶3>5∶5. For the alfalfa component, responses to the mixed sowing systems included reduced plant height and increased stem diameter and leaf area. For the grass component, plant height increased and stem diameter reduced were also observed but leaf area was increased in mild competition and decreased in more intense competition. These responses resulted in a high (>1.0) total relative yield (RYT) value under different mixed sowing ratios. The species in the mixed sown plots adapted to the variations in the interspecific relationship by adjusting their morphological characteristics, and these adjustments provided the mechanism for the achievement of synergistic growth and yield increase. Among the three mixed sown combinations, M. sativa+F. arundinacea exhibited a greater biomass-increasing effect than the others, especially with the legume:grass ratio of 3∶7. In contrast, in the mixed sowings of M. sativa+P. pratensis and M. sativa+B. inermis, the legume∶grass ratio of 7∶3 had the highest biomass-increasing effect.

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    Effects of grazing modes on the community structure and diversity of soil arthropod in an alpine meadow on the Qinghai-Tibetan Plateau
    Cai-cai SUN, Quan-min DONG, Wen-ting LIU, Bin FENG, Guang SHI, Yu-zhen LIU, Yang YU, Chun-ping ZHANG, Xiao-fang ZHANG, Cai-di LI, Zeng-zeng YANG, Xiao-xia YANG
    Acta Prataculturae Sinica    2022, 31 (2): 62-75.   DOI: 10.11686/cyxb2021309
    Abstract367)   HTML18)    PDF (1904KB)(432)       Save

    Soil arthropods are an important component of the soil ecosystem and have been used as “indicators” of environmental change, because of their sensitivity to changes in the surrounding environment. Grazing is the main use of alpine grassland in the Qinghai-Tibet Plateau. Grazing affects both the physical and chemical properties of the soil, and also the biodiversity, including soil arthropods. This research investigated changes in the soil arthropod community structure and diversity associated with grazing by different animal species. Soil arthropods were sampled in July 2020 from a grazing experiment in an alpine meadow on the Qinghai-Tibetan Plateau. The grazing experiment included two single-species grazing treatments (yak only and Tibetan sheep only; YG, SG), three mixed-grazing (MG) treatments (yak: Tibetan sheep ratios of 1∶2, 1∶4 and 1∶6) and an ungrazed control treatment (CK). Soil samples were collected from 0-5 cm, 5-10 cm, and 10-15 cm soil depths, and the soil arthropods were separated by the dry funnel (Tullgren) method, identified, and the data statistically analysed. It was found that: 1) Of the total sampled soil arthropod population, 36.67% belonged to the taxonomic family Acaroidae and 41.14% belonged to the family Oiibatida. The highest densities of arthropods were found in the 0-5 cm soil layer. 2) The composition, community structure, density and diversity of the soil arthropod communities differed between the animal species grazing treatments. Compared with the control , grazing decreased the proportion of Acaroidae, but increased the proportion of Oiibatida in the soil arthropod population. There were significant differences in soil arthropod community structure between CK plots and grazed plots. The species richness index, diversity index and the number of soil arthropods were highest, and the evenness index was lowest in the Tibetan sheep grazing treatment. 3) Soil arthropod evenness index was negatively correlated with soil total nitrogen, total carbon and available potassium (P<0.05 or P<0.01), but positively correlated with soil organic matter and pH (P<0.05 or P<0.01); soil arthropod richness index was negatively correlated with soil pH, but positively correlated with soil total nitrogen, available nitrogen and organic matter contents. Soil arthropod diversity index was negatively correlated with soil pH, but positively correlated with soil total nitrogen, available nitrogen, available phosphorus and organic matter contents. The mean density and the number of groups of soil arthropods were negatively correlated with soil pH, but positively correlated with soil total nitrogen, available nitrogen, available potassium and organic matter. 4) Soil total nitrogen, total phosphorus, total carbon, available nitrogen and available phosphorus levels were higher in the SG treatment. Available phosphorus and organic matter were highest in the CK plots. Soil water content and pH were highest in the MG1:6 treatment. In summary, only Tibetan sheep grazing had a positive effect in increasing soil arthropod density, community composition and community diversity in the alpine grassland ecosystem of the Qinghai-Tibetan Plateau.

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    Genome-wide identification and expression analysis of the bHLH transcription factor family in Cenchrus purpureus
    Li-juan GAO, Zheng-she ZHANG, Yu WEN, Xi-fang ZONG, Qi YAN, Li-yan LU, Xian-feng YI, Ji-yu ZHANG
    Acta Prataculturae Sinica    2022, 31 (3): 47-59.   DOI: 10.11686/cyxb2020593
    Abstract506)   HTML57)    PDF (8489KB)(423)       Save

    The bHLH (basic helix-loop-helix) transcription factor family not only participates in plant growth and development, but also plays a key role in plant response to stress and secondary metabolism. In this study, we identified and analyzed at the whole genome level, the bHLH transcription factor family of Cenchrus purpureus (also called elephant grass, an important forage grass and energy plant). We also analyzed the response of bHLH transcription factors to gibberellin (GA3) and paclobutrazol (PAC) by using transcriptome data and quantitative RT-PCR. A total of 229 bHLH gene family members (CpbHLH001-CpbHLH229), with complete conserved domains, and unevenly distributed on the 14 chromosomes, were identified. The results of phylogenetic analysis revealed that 229 CpbHLHs could be classified into 18 subgroups, of which a subgroup designated C contained the highest number (41). The members of each subfamily had similar gene structures and conserved motifs. Expression profile analysis based on transcriptome data found that most bHLH genes responded to GA3 and PAC in the meristems of the shoot apex, and nine genes with higher expression were randomly selected and further verified by qRT-PCR. It was found that these nine genes were differentially expressed in response to different exogenous GA3 and PAC treatments, suggesting that these genes are associated with GA3 and PAC mediated signaling pathways. This study lays the foundation for further research on the biological functions of the bHLH transcription factor family in elephant grass.

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    Progress in studies of molecular mechanisms and applications of somatic cell regeneration during genetic transformation
    Yu-zhu LI, Jiang-di YU, Fei-fei DING, Jia-min MIAO, Xiao-ming BAI, Shang-li SHI
    Acta Prataculturae Sinica    2024, 33 (2): 198-211.   DOI: 10.11686/cyxb2023147
    Abstract253)   HTML14)    PDF (578KB)(422)       Save

    Plant genetic transformation is the key of transgenic technology, genome editing, functional genomics research and molecular breeding. Species and genotype differences are often the main bottlenecks limiting the efficiency of genetic transformation and the wide application of gene editing technology. With the molecular mechanism of de novo shoot organogenesis and somatic embryogenesis being gradually explored, the growth and developmental regulatory genes involved in the synthesis, response and signal transduction of auxin and cytokinin in callus formation, proliferation and regeneration are used to improve genetic transformation efficiency. In this study, we first review the different ways and means of achieving somatic cell regeneration after genetic transformation, and the molecular mechanisms of regeneration for the transformed cells through indirect organogenesis and somatic embryogenesis. Then, the application of regeneration-promoting genes related to auxin and cytokinin in improving regeneration efficiency, shortening transformation time, and realizing genetic transformation of recalcitrant species and genotypes was discussed. Finally, the potential for application of regeneration-promoting genes when working with transgenic and gene-edited cells were summarized and current research directions were discussed.

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