Table of Content

20 October 2013, Volume 22 Issue 5

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Dynamic monitoring of vegetation water content based on microwave remote sensing in the Qinghai-Tibetan Plateau region from 2002 to 2010

CHEN Si-yu, YU Hui, FENG Qi-sheng, LIANG Tian-gang

2013, 22(5):  1-10.  DOI: 10.11686/cyxb20130501

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Water is an important parameter governing vegetation physiological status and formation structure. The Qinghai-Tibetan Plateau plays an important role in the regional ecological environment and global climate changes, but there is a lack of research on spatial temporal variation of vegetation water content and the relationship between water content and climatic factors. Using the “Leave One Out Cross Validation” (LOOCV) method, an inversion model of vegetation water content was established in the Qinghai-Tibetan Plateau region based on 236 observed data with corresponding AMSR-E daily brightness temperature data. By simulating the distribution of water content in the Qinghai-Tibetan Plateau, the dynamic variations of vegetation water content and the relationship between water content and climatic factor were analyzed from 2001 to 2010. The Microwave Polarization Index (MPI) is superior to the microwave vegetation index in this region, and the power model based on 18 GHz MPI AWC=128.93×MPI^-0.67 has the highest accuracy, and better reflects the condition of the Absolute Vegetation Water Content (AWC). Daily vegetation water content of the Qinghai-Tibetan Plateau in July shows a belt with an increasing trend from northwest to southeast, in which the vegetation water content is mainly below 800 kg/ha in the western and central regions. Compared with the northwest, the southeast vegetation water content has an increased trend, mainly between 800 and 4 000 kg/ha. The inter-monthly variability of vegetation water content has obvious spatial differences in recent years which increases from west to east on the Qinghai-Tibetan plateau. Some relationships between temperature, precipitation and the vegetation water content, show a hysteresis response to rainfall.

Remote sensing estimation and application of grassland NPP based on MODIS data in southern China

SUN Cheng-ming, LIU Tao, TIAN Ting, GUO Dou-dou, WANG Li-jian, CHEN Ying-ying, LI Fei, LI Jian-long

2013, 22(5):  11-17.  DOI: 10.11686/cyxb20130502

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The construction of estimation model with remote sensing for grassland net primary productivity (NPP) is one of the effective ways to realize grassland NPP estimation in large areas. This paper analyzed the relationships between NPP and normalized difference vegetation index (NDVI) based on the moderate-resolution imaging spectroradiometer (MODIS) data and field measurement data. The estimation model of NPP in the southern grassy mountains and slopes was constructed with NDVI as the independent variable and hydrothermal conditions as regulatory factors, and the model was validated by independent observed data in different years. There were five relevant types between the grassland NPP and NDVI, and the correlations all reached a very significant level. There were good correlation and consistency between the simulated and observed NPP, and R² were 0.902 2, 0.826 6, 0.871 2, 0.887 7, 0.875 5, respectively, all achieved a very significant level too. The RMSE and RRMSE between observed and simulated NPP were smaller. It indicated that the model was reliable, and the results of above provided an effective method for the estimation of grassland NPP and the resource management in southern china.

Organic carbon storage in vegetation-soil systems of typical grazing degraded steppes

SARULA, HOU Xiang-yang, LI Jin-xiang, DING Yong, WU Xin-hong, YUN Xiang-jun

2013, 22(5):  18-26.  DOI: 10.11686/cyxb20130503

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Stipa grandis+Leymus chinensis grassland was analyzed for organic carbon storage and distribution in vegetation-soil systems under four different grazing degraded plots (CK:exclosed in 1979, GL:grazed lightly, GM:grazed moderately, GH:grazed heavily). The carbon storage in aboveground biomass was 42.63-203.16 g/m², in belowground biomass (0-40 cm) was 664.14-1 199.53 g/m², and the order in both was CK>GL>GM>GH. The total plant carbon storage in CK and GL were significantly higher (P<0.05) than in GM and GH. There was a significant positive correlation between the carbon storage in aboveground and belowground biomass. The carbon storage in the 0-100 cm soil depth among the different grazing degraded grasslands was 9.85-13.33 kg/m² and they were significantly different from each other in the order GM>GL>GH>CK. The carbon storage was significantly correlated with soil depth and was reduced with an increase of soil depth. The total carbon storage in the vegetation-soil system was 11.26-14.07 kg/m² and was significantly (P<0.05) different between the different grazing degraded grasslands in the order GM>GL>GH>CK. Grassland organic carbon was mostly stored in soil, which accounted for 88%-95% of the storage. There was no significant correlation between soil organic carbon and plant carbon. Moderate grazing can benefit the carbon sequestration function of grassland ecosystems.

The response of grassland plant diversity to soil factors under grazing disturbance

WANG Xing, SONG Nai-ping, YANG Xin-guo, YANG Ming-xiu, XIAO Xu-pei

2013, 22(5):  27-36.  DOI: 10.11686/cyxb20130504

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The effect of sheep dung return presenting a certain pattern of gradient distribution in spatial was a very important factor which effected the spatial distribution of soil and vegetation and dynamics of succession in meadow with free grazing conditions. In order to develop a deeper understanding on the effect of grazing to the pattern of influencing and the mechanism of action of meadow in desert steppe. we conducted a research that the grass plant diversity and the relationship between plant diversity and soil environmental factors were studied by setting up six gradient sequence sample (1.41—1 581.68 g/m²) according to the natural surface of sheep dung quantity gradient in Ningxia desert steppe ecosystem. The results showed that plant community presented a trend which the dominance status of Penniseluru cenlrasialicuru was substituted by Sophora alopecuroides: the importance value of cenlrasialicuru decreased from 2.07 to 0.19, the importance value of alopecuroides increased from 0 to 1.25. The plant diversity index of margalef increased from 0.64 to 2.26, Shannon-Wiener increased from 0.35 to 1.86 respectively but the index of Pielou was not necessarily change rule with the increase of grazing intensity. The main soil environment factors affecting the plant diversity were soil total nitrogen as the significant one, moisture content and available nitrogen at 0-5 cm soil layer, soil organic carbon and nitrogen as the significant one at 5—10 cm soil layer respectively. Preliminary research conclusions considered the one most important factor affecting the plant diversity was the increasing of soil nitrogen and this result may be related to nutrient return of grazing livestock excreta. Confirming where the nitrogen comes from and goes to may be the primary mission in further recognizing of the mechanism of action about sheep dung return in the grassland ecosystems of desert steppe.

Analysis of available nutrients contents in Suniteyou Banner pasture soils

TA Na, NA Ri-su, WANG Hai, SHI Tao

2013, 22(5):  37-43.  DOI: 10.11686/cyxb20130505

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The study of surface soil available nutrients (total N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, B and Mo) contents and the correlations with soil organic matter and pH value was conducted in 8 styles among of 6 types of grassland from Suniteyou Banner. The results showed as follows, 1) The soils from study area belong to alkaline soil, pH was (8.84±0.23). The content of soil organic matter and total N was low, averaged in (9.92±4.65) g/kg and (0.46±0.25) g/kg respectively. The accumulation of soil available nutrients displayed an order as River pan and lake basin lowlands salt meadow pasture>“Stipa klemenzii+Cleistogenes songorica+Allium” in desert steppe pasture>Dune vegetation pasture. The content of soil available nutrients in River pan and lake basin lowlands salt meadow pasture was significantly higher than those in other grassland types. 2) Soils were rich in K but lack of B and Mo seriously. Soil in different grassland types showed in lack of trace elements except of River pan and lake basin lowlands salt meadow pasture. 3) Soil pH value displayed significant negative correlation with available N, P, Ca, Mn and Cu. On the contrary, soil organic matter showed significant positive correlation with available N, P, Ca, S, Fe, Mn and Cu.

Belowground biomass and features of environmental factors in the degree of grassland desertification

JIN Yun-xiang, XU Bin, YANG Xiu-chun, LI Jin-ya, MA Hai-long, GAO Tian, YU Hai-da

2013, 22(5):  44-51.  DOI: 10.11686/cyxb20130506

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Belowground biomass is the important component of carbon accumulation on grassland, and the main link to relate aboveground with belowground ecosystem process. In order to discuss variation of belowground biomass in succession process of grassland desertification, taking grassland on Zhenglan Banner of Inner Mongolia as example, we analyzed its distribution pattern and soil environment features in different desertification grassland by the sample-plot survey method. We proceed with significance testing by one-way variance analysis (One-way ANOVA) and Scheffe method. The results showed that: 1) Belowground biomass decreased with soil depth and with a ‘T’ shape distribution. Belowground biomass in 0-30 cm soil layer occupied more than 80% of the total and then was significantly declined with the aggravation of grassland desertification (P<0.05). Belowground biomass of non-desertified grassland was the highest (2 598.67 g/m²), and was followed by slight desertified grassland (2 318.45 g/m²), moderate desertified grassland (390.26 g/m²) and severe desertified grassland (117.25 g/m²). 2) Soil temperature decreased with soil depth and remained stable under 30 cm soil layer. Soil moisture content of grassland desertification in deep soil layer was a little more than soil moisture content in surface layer. Water retaining capacity of non-desertified grassland preceded its desertified grassland. 3) Following succession process of grassland desertification, soil physicochemical properties occurred a series of variation. Sand content increased significantly compared with non-desertified grassland and occupied more than 90%. In general, pH value of soil on temperate grassland belonged to neutral. There was non-significant difference of pH value between the various types of desertified grassland (P>0.05). Following the aggravation of grassland desertification, soil organic matter, total nitrogen and available nitrogen content of desertified grassland were significantly lower than non-desertified grassland (P<0.05). The others nutrient content were non-significant difference. Through researching distribution pattern and soil environment features in different desertification grassland, this paper has provided effective data foundation and reference value with accuracy estimation of belowground biomass. Meanwhile, it has been the important significance to research distribution and gross of roots and enhance accuracy root module in model application.

Phenotypic variation of wild Miscanthus sinensis populations from southwestern China

NIE Gang, ZHANG Xin-quan, HUANG Lin-kai, XU Wen-zhi, MA Ying-mei

2013, 22(5):  52-61.  DOI: 10.11686/cyxb20130507

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Bioenergy is considered as the most promising energy source under the energy crisis in the 21st century. Miscanthus sinensis is a very good bioenergy candidate because of its high biomass, good burning quality, environmental tolerance, and tolerance of marginal land for growth. To investigate the phenotypic variation and relationships of different wild M. sinensis populations collected from southwestern China, a project was carried out to study nine botanical characteristics and yield characters of 37 wild M. sinensis populations. There were significant differences (P<0.01) between populations in all characteristics studied. Abundant morphological variation was detected in accessions of M. sinensis and their coefficients of variation were ranked as follows: dry weight of individual plant (46.89%)＞fresh weight of individual plant (46.34%)＞tiller numbers (44.08%)＞flag leaf length (33.99%)＞flag leaf width (27.40%)＞leaf width (19.59%)＞internode number (18.76%)＞internode length (18.49%)＞stem diameter (17.89%)＞plant height (14.64%)＞leaf length (12.83%). Phenotypic characteristics of M. sinensis were also significantly correlated. Those accessions with long and wide leaves were tall plants with longer and wider flag leaves, wider stems, but fewer tillers, and vice versa. In addition, the weight of individual plants was significantly correlated with tiller numbers, plant height, and leaf length which suggests that these characteristics should be improved and evaluated for future applications. Principal component analysis based on nine morphological characteristics showed that four principal components reflected most of the plant phenotypic characteristics. Thirty-seven populations were divided into 3 categories based on Euclidean distance clustering analysis which included tall plants with long and narrow leaves, tall plants with long and wide leaves, as well as short plants with short and narrow leaves.

Assessment of vegetation by object-oriented classification and integration of decision tree classifier in Yushu

WANG Zhi-wei, SHI Jian-zong, YUE Guang-yang, ZHAO Lin, NAN Zhuo-tong, WU Xiao-dong, QIAO Yong-ping, WU Tong-hua, ZOU De-fu

2013, 22(5):  62-71.  DOI: 10.11686/cyxb20130508

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The classification of vegetation has attracted much attention for study of ecological effects on the Qinghai-Tibetan Plateau. Previous studies have mostly focused on decision tree classifiers, and much research has been done to test this classification on a small scale. In this study, we consider a large scale method (object-oriented classification), which can also be integrated with a conventional decision tree classifier. However, the rules of classification have only utilized the information from decision tree classifiers. This approach comprehensively considered information of position, terrain and texture from TM (thematic mapper), DEM (digital elevation model), EVI (enhanced vegetation index) and LST (land surface temperature) in Yushu, and then segmented or merged the type of steppe. The overall accuracy is 49.32%, and Kappa coefficient is 0.373 5. Our study suggested that this method could overcome the disadvantages of scattered pixels when division is by the type of vegetation. Compared to the conventional decision tree classifier, the overall precision of our method is low. However our method maintained the statistical relationship between factors derived from the environment and geography, and vegetation types to reduce the salt and pepper effects. In addition, the physical process, parameter calculations and environmental factor collection of vegetation models are complicated. In this paper, a simple and quick way of division of vegetation types is provided by our method.

Genetic improvement of perennial ryegrass with low lignin content by silencing genes of CCR and CAD

HU Ke,YAN Xue-feng,LI Dan,TANG Xiao-mei,YANG Hong,WANG Yan,DENG Hong-yuan,MA Xin-rong

2013, 22(5):  72-83.  DOI: 10.11686/cyxb20130509

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Lignin, one of the main components in vascular plants, is mainly present in the walls of secondarily thickened cells. However, it is a limiting factor in a number of agro-industrial processes, such as chemical pulping, forage digestibility, and lignocellulosic-to-bioethanol conversion. Cinnamoyl CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD) are two key enzymes that catalyse the penultimate and ultimate steps respectively in the biosynthesis of monolignols. Based on the CCR and CAD gene sequences of perennial ryegrass (Lolium perenne) from NCBI, specific primers were designed to add appropriate restriction enzyme sites to amplify and clone the two gene fragments from cDNA of perennial ryegrass. Two RNA interference (RNAi) vectors (p23-iCCR and p23-iCAD) were constructed using inverse repeat fragments. The constructs were introduced into embryogenic calli of perennial ryegrass by Agrobacterium-mediated transformation with EHA105. They were screened using paromomycin and detected by PCR, and independent i-CCR and i-CAD transgenic plants were obtained. Analysis of relative lignin content was conducted by conventional methods. The lignin content was distinctly reduced compared with that of wild controls in 9 plants of i-CCR and 11 plants of i-CAD transgenic plants. The lignin content of these i-CCR and i-CAD plants was reduced by 34.67％ and 33.86％ respectively. The transgenic plants had normal morphology and grew well. This study showed that low-lignin-content perennial ryegrass could be obtained by silencing CCR and CAD gene expression and has provided novel germplasms for breeding digestible and improved absorption ryegrass.

Screening molecular markers for heat tolerance and its relation to summer tolerance in tall fescue single plants

CHEN Qun, YUAN Xiao-jun, HE Ya-li

2013, 22(5):  84-95.  DOI: 10.11686/cyxb20130510

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To establish an efficient breeding system in tall fescue (Festuca arundinacea), molecular markers related to heat and summer tolerances were screened for marker-assisted selection breeding. Initially, 216 single plants from 12 germplasms differing in heat tolerance were used as a basic population to identify their heat stress (40℃/35℃, day/night, 12 h/12 h) tolerance in an artificial climate chamber and their summer stress tolerance in experimental fields in Shanghai. Random amplified polymorphism DNA (RAPD) and inter-simple sequence repeat (ISSR) were assessed with modified bulked-segregant analysis (BSA) to screen for molecular markers among the 800 RAPD and 100 ISSR primers. The correlation between heat and summer tolerance among single plants was quite low with only 3.4% of the determination coefficient; Primer “351” amplified a 750 bp band (351-T750) which was significantly related to heat tolerance, while “138” amplified a 950 bp band related to both heat and summer tolerance. Heat and summer tolerant single plants should be screened under artificial heat and natural summer stresses respectively; Band 351-T750 could be used only for heat tolerant plant selection, while 138-T950 could be used for both heat and/or summer tolerant plant selection.

3′ end cloning and sequence analysis of the FTH gene from Chinese Holstein cattle

LUO Jia-jie, PENG Ying, LUO Rui, ZHANG Bin, LI Li-li, WU Li-zhuan, ZHAN Jin-shun, XING Yue-teng

2013, 22(5):  96-103.  DOI: 10.11686/cyxb20130511

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The 3′ end cDNA sequence and amino acid sequence of the FTH (ferritin) gene from Chinese Holstein cattle was cloned and analyzed to provide a theoretical basis for functional studies and its effective utilization. The 3′ end cDNA was cloned from liver tissues by rapid amplification of cDNA ends (RACE), and the bioinformatics method was used to analyze the amino acid sequence. The 3′ end cDNA of the FTH gene was 489 bp and it encoded a peptide of 81 amino acids. Its relative molecular weight was 9.125 3 kD, isoelectric point was 5.19, fat index was 85.56, grand average of hydropathy was -0.342. N-terminal signal peptides and transmembrane domains were not included in this protein. The primary structure of the FTH protein contained four functional domains, and the secondary structure was mainly an α-helix with β-rotation. The results obtained through homologous sequencing indicated that the FTH of Chinese Holstein cattle had a high similarity to that of Bos taurus (99%), and the molecular evolution trees showed that the FTH of Chinese Holstein cattle had very low genetic relationships with other species studied in this research. These results provided clues for evolutionary studies of the FTH gene family, as well as serving as references for further functional analysis and utilization.

Effects of bio-fertilizers with different PGPR strain combinations on yield and quality of alfalfa

HAN Hua-wen, SUN Li-na, YAO Tuo, RONG Liang-yan, LIU Qing-hai, LU Hu, MA Hui-ling

2013, 22(5):  104-112.  DOI: 10.11686/cyxb20130512

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In recent years, bio-fertilizers have emerged as an important component of the integrated nutrient supply system and hold great promise to improve crop yields because increasing use of chemical fertilizers and high productive systems are creating environmental problems. The effects of different combinations of PGPR strains on yield and quality of alfalfa (Medicago sativa) were studied in randomized block field experiments using bio-fertilizers. These were produced using different combinations of three phosphate solubilizing bacteria (Bacillus sp., Pseudomonas sp. and Azotobacter sp.) and one rhizobium (Sinorhizobium meliloti) strain isolated from the rhizosphere of alfalfa and wheat. Hay yield and quality of alfalfa decreased when treated with mono-strain bio-fertilizer (containing 50% phosphatic fertilizer) compared with the control (100% phosphatic fertilizer) although there was no significant difference. Hay yield, content of crude protein (CP), calcium, phosphate and ether extract (EE) increased 10.6%, 16.4%, 14.1%, 11.9% and 4.2% respectively, while acid detergent fiber (ADF) and neutral detergent fiber (NDF) were reduced by 10.9% and 7.7%. The benefit of mono strain bio-fertilizer was inferior to that of mixed strain bio-fertilizer. Strains S7 and Jm170+Jm92+Lx191+S7 with 50% phosphatic fertilizer are recommended as the best treatments to substitute for 100% phosphatic fertilize in alfalfa production.

Diversity and community structures of the endophytic actinomycetes isolated from Medicago ruthenica

ZHANG Bo, LI Xiao-lin, JIANG Hua-ming, ZHANG Xiao-ping

2013, 22(5):  113-119.  DOI: 10.11686/cyxb20130513

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The denaturing gradient gel electrophoresis (DGGE) method was applied to investigate the diversity and community structures of the endophytic actinomycetes isolated from the different tissue parts of Medicago ruthenica grown in Ganzi, Sichuan Province. The result indicated that the diversity and community structures of the endophytic actinomycetes were significantly different among the plant tissue parts of root, stem, leaf and flower. The highest diversity index (H) and richness (S) were found in the plant flower, then, in the root, stem and leaf, respectively. The eveness (E_H) of the actinomycetes was higher in the leaf, than that in the root, stem and flower, respectively. The similarity of the community structures was significantly different among the plant tissue parts, except that between the leaf and stem. The results of DGGE bands sequencing showed that the majority of the clones were the genus Streptomyces, the rest of 43% clones were rare actinomycetes. In addition, the dominant band A23 and common band A12 also showed the clone of rare actinomycetes, which indicated that some rare actinomycetes were the dominant species in the medicinal plant M. ruthenica. All of the results in this work revealed the high diversity of endophytic actinomycetes in the plant tissues of M. ruthenica, and the richest was found in the flower. M. ruthenica in Ganzi should be a good plant resource for isolation of endophytic actinomycetes.

The effect of symbiotic rhizobium on the antioxidative and osmoregulatory capability in alfalfa under salt stress

WANG Wei-dong, YANG Pei-zhi, ZHANG Pan, HAN Bo, ZHANG Zhi-qiang, CAO Yu-man, HU Tian-ming

2013, 22(5):  120-127.  DOI: 10.11686/cyxb20130514

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To understand whether nodulation affects salt stress response in alfalfa (Medicago sativa), we analyzed the content of methane dicarboxylic aldehyde (MDA), superoxide anion radical, activity of superoxide dismutase (SOD), glutathione (GSH), proline, and soluble sugar in alfalfa under salt stress. Four-month-old alfalfa plants without nodules, with active nodules, or with inactive nodules were treated for 0, 5, 10 and 15 days. Alfalfa plants with nodules, especially with active nodules, had less MDA. The MDA contents of roots, stems, and leaves reached a low point, of 3.90, 0.53, 4.16 mmol/g DW respectively at the 15th day. The least superoxide anion radical and the SOD activities of roots, stems, and leaves were highest in the 15th day with activities of 1 592.48, 1 317.86, 2 068.88 U/g DW·h, respectively and with stable GSH, but unstable content of proline and soluble sugar. The results suggested that alfalfa with active nodules may have higher osmoregulatory and antioxidative capability under salt stress.

Effects of four host plants and different cultivation densities on the propagation of arbuscular mycorrhizal fungi

2013, 22(5):  128-135.  DOI: 10.11686/cyxb20130515

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To establish a propagation system for arbuscular mycorrhizal (AM) fungi, four different plants: maize (Zea mays), sorghum (Sorghum bicolor), white clover (Trifolium repens) and green onion (Allium fistulosum) were selected for this study. Two different cultivation densities were used to test the influence of plant densities on the propagation of an AM fungus (Glomus versiforme). Different plant species and different densities had a significant influence on the colonization and spore production of G. versiforme and on the biomass of host plants (P<0.05). The extent of AM colonization and spore densities at 10 plants per pot were much higher than at 5 plants per pot (P<0.05). Our studies suggest that maize, which has the highest biomass with high density, was suitable for propagation of G. versiforme.

Rapid detection of Rhizoctonia in rhizosphere soil of potato using real-time quantitative PCR

LI Rui-qin, LIU Xing, QIU Hui-zhen, ZHANG Wen-ming, ZHANG Chun-hong, WANG Di, ZHANG Jun-lian, SHEN Qi-rong

2013, 22(5):  136-144.  DOI: 10.11686/cyxb20130516

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A leading obstacle to continuous cropping of potatoes is Rhizoctonia solani in the rhizosphere. An understanding of the relationship between potato soil-borne pathogen accumulation and continuous cropping was sought to overcome the obstacles to continuous cropping of soil borne diseases. Synergy Brands (SYBR) Green I Dye (SGI) real time fluorescent quantitative Polymerase Chain Reaction (Rt-PCR) was optimised to perform quick checks and quantification of R. solani in soils with potato damping off disease. The dynamic changes of R. solani in the rhizosphere soil of continuously cropped potato was investigated. Results show that, the methods can be directly applied to soil pathogens with quantitative detection of DNA, which can be detected to a minimum detection level of 1×10² copies/g in potato soil concentrations of R. solani. Amplification efficiency is high (1.04) with a low detection limit. The cumulative status of pathogenic bacteria in the rhizosphere soil can be readily assessed without isolation and culturing. With increasing years of continuous potato cropping, the numbers of R. solani in rhizosphere soil had an upward trend with the increasing year of potato’s continuous cropping, by the growth process, the numbers of rhizoctonia solani in rhizosphere soil were downward trend. The largest amount of pathogens accumulated is the pre-seeding period of five years, that is 3.75×10⁷ copies/g. This shows that continuous cropping led to a soil microbial population structure that increased the amount of change of soil pathogenic fungi. The infection probability of Rhizoctonia solani in early potato blight increased.

Effects of exogenous nitric oxide on seed germination and seedling oxidative damage in Medicago sativa under NaCl stress

XU Yan, WEI Xiao-hong, LI Bing-bing, CAO Li, TANG Zhi-ming

2013, 22(5):  145-154.  DOI: 10.11686/cyxb20130517

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1) Medicago sativa seeds were soaked in two concentrations (0.1 and 1.0 mmol/L) of sodium nitroprusside (SNP) for 48 h. Samples of 50 seeds taken on 10 consecutive days were cultured in dishes under conditions of constant light and temperature at (25±1)℃.NaCl solution (6 mL 0.15%) was added to investigate the effects of exogenous nitric oxide on seed germination under NaCl stress. 2) The influence of the exogenous nitric oxide donor (SNP) at concentrations of 0.1 and 1.0 mmol/L on M. sativa seedling leaf oxidative damage under 0.15% NaCl stress were studied for 8 days of treatment. The treatments were, T1: CK (distilled water); T2: 0.15% NaCl; T3: 0.1 mmol/L SNP+0.15% NaCl; T4: 1.0 mmol/L SNP+0.15% NaCl. The results indicated that germination rate (P＜0.01), germination energy, germination index (P＜0.05) and vigor index (P＜0.05) of M. sativa seeds were dramatically promoted by SNP treatments during germination under 0.15% NaCl stress. The activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), were increased, which is consistent with the up-regulation of proline and soluble sugars, and with the down-regulation of O₂^- production, speed and content of malondialdehyde (MDA), H₂O₂ and chlorophyll in M. sativa seedling leaves compared with those under salt stress. Meanwhile, the protective ability of concentrations of 0.1 mmol/L was significantly better than those of 1.0 mmol/L.

Seedling banks and their relationship with the standing vegetation under different erosion environments in the hill-gully Loess Plateau region

SU Yuan, JIAO Ju-ying, WANG Qiao-li, DU Hua-dong, WANG Zhi-jie, KOU Meng

2013, 22(5):  154-164.  DOI: 10.11686/cyxb20130518

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Seedlings are an indispensable stage in the plant cycle life and are important in natural vegetation restoration. The objective of this paper was to explore seedling characteristics and their relationship with the standing vegetation under different erosion environments in the hill-gully Loess Plateau region. Three typical watersheds in different vegetation zones were selected, and One-Way ANOVA was used to analyze seedling densities, species diversity and the similarity between seedlings and the ground vegetation using quadrat surveys. In the seedling bank,there were 75 species belonging to 25 families, while in the ground vegetation there were 105 species belonging to 29 families. Most species were Compositae, Gramineae and Leguminoseae composited. while Xerophytic and Mesoxerphytic were the main water ecotypes, and perennial herbs were the dominant life-form. Seedling densities and diversity were different in different erosion environments. They were greater in the forest-grassland and grassland zones than in the forest zone. In the same vegetation belt, seedling densities in the Dongzigou watershed was in the order mao top>shady slope>sun slope, while diversity was in the order liang/mao slope>gully slope. In the Gaojiagou watershed, there was no significant difference in seedling density or diversity. In the Zhangjiahe watershed, seedling densities were bigger and species were richer on shady slopes, especially on shady gully slopes. Different erosion environments had no significant effect on the similarity between seedlings and the standing vegetation. The Sorensen similarity index of herbs in the 3 watersheds was less than 0.5, showing smaller similarity. Therefore, the site conditions in the hill-gully Loess Plateau region are poor, and the seedlings cannot survive and establish easily.

Contribution of winter wheat leaf and non-leaf organs to grain weight

LU Qing-lin, CHAI Shou-xi, ZHANG Li-jun, ZHOU Gang

2013, 22(5):  165-174.  DOI: 10.11686/cyxb20130519

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To search for new methods of increasing grain weight and to mine yield potential, a two-year study on contribution of top four leaves and non-leaf organs (head, sheaths and stalk) to grain weight was carried out from 2011 to 2012 through selecting 12 different winter wheat cultivars (lines) and designing 21 treatments of leaves removal and shading. Contribution rate of top 4 leaves to grain weight was 17.8%, flag leaf, second leaf, third leaf and forth leaf was respectively 10.60%, 2.80%, 0.05% and 1.60%. Contribution rates of head, sheaths and stalk was respectively 41.0%, 11.0% and 5.7%. There existed relatively large differences among varieties. By correlation analysis, the positive correlations were found between height, head leave area and contribution rate of flag leaf and second leaves, and also between head stalk, plant height and contribution rate of stalk and sheaths. The negative correlations were found between plant height and contribution rate of third leaf and forth leaf, and also between plant height, head stalk, top 4 leaves area, flag leaves area and head contribution. Consequently, it was conducive in increasing grain weight to select cultivars with great contribution of leaves and no-leaf organ to grain weight.

Effects of seed ultra-drying storage on growth and resistance of Medicago sativa seedlings affected by neutral salt stress

HUO Ping-hui, LI Jian-feng, SHI Shang-li, ZHANG Shu-qing

2013, 22(5):  175-182.  DOI: 10.11686/cyxb20130520

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In order to make clear the effect of seed ultra-drying to growth and resistance of the resulting seedlings, Medicago sativa cv. Longdong was used to be differently desiccated with silica gel method, and pot culture with sand and neutral salt stress was conducted after 1 year storage. The result indicated that after moderate ultra-drying, seedling emergence, plant leaflet number (60 days), root volume, root length and soluble sugar content increased 53.33%—66.67%, 14.02%—58.34%, 36.22%—194.22%, 13.75%—18.66% and 31.5%—36.81%, respectively, while MDA content decreased to 18.09%—74.51%, compared with the control; no significant tendency was found between shoot height/chlorophyll content and seed moisture content; mild desiccation treatment accelerated plant biomass, while consistent seed moisture content decrease restricted plant biomass; root activity (4.59% treatment excluded) and nodule number of each treatment were significantly lower than or with no difference compared with the control, indicating that moderate seed ultra-drying and storage accelerated seedling emergence, leaf and root growth for seedlings grown under neutral salt stress, strengthened plant osmosis regulation and decreased adverse stress, but had no promotion in nodule generation or even affected its formation.

Effects of exogenous hormones on the dormancy and germination of Leymus chinensis

HUANG Xiao-hui, HU Xiao-wen, XU Zong-hai, WANG Yan-rong

2013, 22(5):  183-189.  DOI: 10.11686/cyxb20130521

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To study the effects of plant hormones on the seed dormancy and germination of Leymus chinensis, three exogenous hormones including Abscisic acid (ABA), Gibberellin 3 (GA₃), Gibberellin 4+7 (GA₄₊₇) and their biosynthetic inhibitors were used to treat seeds. Seed germination was not affected by low exogenous ABA concentrations, but was significantly reduced at the highest concentration. This reduction was reversed by FL application indicating that ABA biosynthesis may play a critical role in maintenance of seed dormancy. The type of gibberellin affected its effect: GA₄₊₇ significantly promoted seed germination, but GA₃ had no effect. Percentage seed germination significantly decreased after immersion in PA which is a biosynthesis inhibitors of GA, but this effect can be reversed by exogenous GA₃. This shows that GA is necessary for non-dormant seed germination. This was further confirmed by a combination of PA plus FL treatments, which inhibited ABA biosynthesis during imbibition, although the percentage seed germination still decreased. In addition, 8 weeks cold stratification in FL can significantly break seed dormancy of L. chinensis, but other media can induce secondary dormancy, a process that may be related to an increase of ABA during imbibition.

Effects of estrogen stress on seed germination, seedling growth and accumulation in radish

WEI Rui-cheng, LI Jin-han, HE Long-xiang, WANG Ran, SHAO Ming-cheng, ZHENG Qin

2013, 22(5):  190-197.  DOI: 10.11686/cyxb20130522

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The effects of different concentrations of 17β-estradiol (17β-E2) on seed germination, seedling growth, antioxidant enzyme system and 17β-E2 accumulation in radish (Raphanus sativus) were investigated using water culture method. The results indicated that the germinating potentiality, germination rate and root elongation of radish presented the inverse correlation with 17β-E2 treatment. The germinating potentiality and root elongation of radish were obviously increased and activities of SOD, POD and CAT of radish were significantly enhanced by 17β-E2 at levels of 10 μg/L. The 50 μg/L 17β-E2 treatment inhibited the activities of SOD, POD and CAT and significantly stimulated an increase in the content of MDA. It made seedling oxidation resistance significantly decrease and finally resulted in aggravate of the lipid peroxidation. With rising treatment concentration, the content of 17β-E2 accumulated in seedlings was increased. The content of 17β-E2 in the root was larger than that in aerial part. In the transportation process, 17β-E2 was partly metabolized into the low active estrone in radish. The experiments revealed that radish showed a certain tolerance to 17β-E2 stress, so there was a potential food risk posed to mankind health for radish growing in estrogen-contaminated soils.

An evaluation of mixed-ensiling sunflower straw and whole corn on silage quality

YU Jie, ZHENG Chen, LI Fa-d, GUO Yan-li, ZHAO Dong

2013, 22(5):  198-204.  DOI: 10.11686/cyxb20130523

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Different mixtures of sunflower (Helianthus annuus) straw and whole corn maize (Zea mays) were used in a single factor experiment. The sensory evaluation, nutrient content and fermentation quality of all treatments were determined and analyzed to assess the best ratio of sunflower straw and whole corn maize for mixed silage. Sunflower straw and whole corn maize were mixed in the following proportions by weight: 0∶10, 4∶6, 5∶5, 6∶4, 7∶3, 8∶2, 9∶1 and 10∶0. Sunflower straw could be ensiled successfully although it was a composite herbage and the primary fermentation was heterolactic fermentation; After ensiling sunflower straw and whole corn maize in the proportion of four to six, the contents of DM (dry matter), CP (crude protein) and EE (ethanol extract)in the mixed silage was significantly higher than that in the sunflower straw silage while the contents of Ash (crude ash)、NDF (neutral detergent fiber)、ADF (acid detergent fiber)、Ca and P was much lower (P<0.01). The pH value of all the mixed groups of silage was lower than 4; LA (lactic acid content)/TA (total acid) and PA (propionic acid)/TA ratios in all the mixed groups of silage were improved compared with sunflower straw silage while that of AA/TA was reduced; There was no BA (butyric acid)/TA in any of the mixed groups of silage. Of all the mixed treatment groups, NH₃-N/TN (total N) was lower than that of the sunflower straw silage. It was concluded that sunflower straw and whole plant maize mix-ensiling improved the quality of sunflower straw silage.

Influence of different fertilizer formulations on the growth of safflower (Carthamus tinctorius) on secondary salinization soil in a drought irrigation area

ZHANG Xin-yang, JIN Xiao-jun, TANG Wen-wen, XU Xue-jun

2013, 22(5):  205-211.  DOI: 10.11686/cyxb20130524

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A field experiment was conducted to investigate the influence of different fertilizer formulae on the growth of safflower (Carthamus tinctorius) on a secondary salinization soil in a drought irrigation area. Application rates of N, P, and K was designed with a “3414” strategy, a method generally used for fertilization formulae experiments. Application rates of N, P, and K had significant effects on plant height, ramose tallness, numbers of flowers, yield of flowers, and grain yield of Safflower. N₂P₂K₂ (namely N∶P∶K=180∶90∶120) treatment gave the highest yield of flowers and grain production. A step by step regression curve was done to determine the relationship of corolla production and grain yield of Safflower with application rates of N, P and K. It showed that a fertilizer application rate of N 150.59 kg/ha, P₂O₅ 93.09 kg/ha and K₂O 98.75 kg/ha was good for corolla production, and the highest theoretical yield was 667.98 kg/ha. For grain yield, the best fertilizer application rate was N 169.50 kg/ha, P₂O₅ 94.60 kg/ha and K₂O 102.75 kg/ha, giving the highest theoretical grain yield of 2 644.47 kg/ha on secondary salinization soil in a drought irrigation area.

Effects of shade on the photosynthetic characteristics and chlorophyll fluorescence parameters of three kinds of leguminous forage

ZHANG Zhe, YANG Shu, DU Gui-juan, HUANG Shu-ping, MA Feng-jiang

2013, 22(5):  212-219.  DOI: 10.11686/cyxb20130525

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To investigate the ecological adaptability of leguminous forage under different shade conditions and seek appropriate shading proportions, the photosynthetic characteristics and chlorophyll fluorescence parameters of three kinds of leguminous forage were determined under three shade conditions (0%, 48%, 70%, 95%). The results of the experiment showed that the light compensation point (LCP) and light saturation point (LSP) of Trifolium repens were at a low level. Medicago sativa and Melilotus suaveolens could maintain low LCP and LSP in the appropriate shade conditions, but they decreased with an increase in shade. The content of chlorophyll a, chlorophyll b and total chlorophyll a+b ratio in leaves decreased with increasing shade and the levels in T. repens were higher than those in the other two f legumes in the same shading treatments. The chlorophyll a/b ratio maximum performance of M. sativa was in the Y3 treatment. The order of leguminous forage for sensitivity to PSⅡinjury was: M. sativa＞M. suaveolens＞T. repens; The ΦPSⅡ and qP of T. repens and M. suaveolens were slightly reduced with shading, while those of T. repens were slightly increased under Y3 treatment conditions, and the M. sativa initially increased but then decreased with an increase of shading.The shading intensity sequence of the three kinds of leguminous forage was: T. repens＞M. suaveolens＞M. sativa. T. repens could still grow well in more than 70% shade, M. suaveolens were grew well under 48% shade, and M. sativa was greatly affected by shade.

Algorithm improvements for two important parameters of FPAR and maximum solar energy utilization efficiency

WANG Bao-lin,WANG Jing-jie,YANG Yong,CHANG Shu-juan, CHEN Xi-mei, LIU Ai-jun

2013, 22(5):  220-228.  DOI: 10.11686/cyxb20130526

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Photosynthetically active radiation and solar energy utilization efficiency are two of the most important parameters in NPP (net primary productivity) simulation. The solar effective radiation value of key phenological phases for typical steppe was tested using the light quantum instrument, and two models for FPAR (fraction of photosynthetically active radiation) estimation according to correlation between NDVI (normalized difference vegetation index) and FPAR were established. The correlations between measured and estimated FPAR values were significant, and there was no significant difference between the two groups value of model estimation. Therefore, mean values of estimated FPAR were calculated, and nested with NASA (national aeronautics and space administration)-FPAR products, to form a complete FPAR spatial distribution map of grassland in China. In addition, the study also adjusted maximum solar energy utilization efficiency of 18 categories of grassland in China based on normalized difference vegetation index (NDVI) and leaf area index (LAI). The result also showed that adjustment of maximum solar energy utilization efficiency could improve accuracy (85.71% at larger scale) of NPP estimation after inputting the NPP model.

Effects of drought preconditioning on physiological responses to heat stress in two Kentucky bluegrasses

PENG Yan, LI Zhou

2013, 22(5):  229-238.  DOI: 10.11686/cyxb20130527

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The effect of improved heat tolerance through drought preconditioning on responses to drought preconditioning under heat stress was studied in two Kentucky bluegrasses. Plants of Kentucky bluegrass (Poa pratensis) cultivars “Midnight” (drought resistant) and “Brilliant” (drought sensitive) were well watered (non-preconditioned control) or exposed to two cycles of drought stress without irrigation (drought preconditioning) and then exposed to heat stress (35℃/30℃, day/night) for 25 days in growth chambers. Turf quality and other physiological parameters in leaves were determined at 0 (end of drought preconditioning and beginning of heat treatment), 5, 10, 15, 20, and 25 days of heat treatment. During the period of heat stress, drought-preconditioning of cv. “Brilliant” resulted in significantly (P＜0.05) higher turf quality compared with the non-preconditioned “Brilliant”. After 5 days of heat stress, osmotic potential gradually declined in drought-preconditioned “Brilliant”, but there was little change in the non-preconditionied “Brilliant”. Plants of drought-preconditioned “Brilliant” maintained significantly (P＜0.05) higher relative water content than those of non-preconditioned plants at 10 and 15 days of heat stress. The activities of superoxide dismutase and catalase were significantly (P＜0.05) higher in drought-preconditioned “Brilliant” than in non-preconditioned “Brilliant” at 10 and 20 days of heat stress, but electrolyte leakage was the reverse. There was significantly (P＜0.05) higher fatty acid (16∶0 and 18∶0) content in drought-preconditioned “Brilliant” than in non-preconditioned “Brilliant” after 15 days of heat stress, although the content of 18∶3 was the opposite. Drought-preconditioned “Midnight” had a higher double bond index (DBI) than non-preconditioned “Brilliant”. The physiological parameters were not significantly different in the two treatments in “Midnight” under heat stress. In conclusion, drought preconditioning improved heat tolerance in the drought sensitive cv. “Brilliant” but failed to improve heat tolerance in the drought resistant cv. “Midnight'. Improved heat tolerance through drought preconditioning in “Brilliant” was associated with increased osmoregulatory ability and the promotion of antioxidant activities which can protect unsaturated fatty acids from damage. These changes may play an important role in improving leaf relative water content, protecting membrane systems and delaying leaf senescence.

Evaluation of shade tolerance of nine warm-season turfgrass and selection of their shade tolerant indices

LUO Yao, XI Jia-bin, TAN Xiao-hong, ZHANG Ju-ming

2013, 22(5):  239-247.  DOI: 10.11686/cyxb20130528

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Shade tolerance of nine warm-season turfgrass was carried out by evaluating 12 morphological and physiological indices: leaf area, leaf length, leaf length to width ratio, internode length, biomass, chlorophyll a content, chlorophyll b content, total chlorophyll content, soluble sugar, POD activity, Fv/Fm and Fv/Fo, all of which are closely correlated with shade tolerance. Each index value was converted into the relative value of shade tolerance compared with the full light control. Using correlation analysis and principal component analysis, the 12 indices were transformed into four mutually independent comprehensive variables, and then each index value and its corresponding subordinate function value were calculated. After a comprehensive evaluation of each varieties shade tolerance, the rank of the nine turfgrass shade-tolerance from strong to weak was: Axonopus compressus cv. Zhongda 1, Stenotaphrum helferi, Stenotaphrum helferi ‘golden’, Zoysia japonica cv. Lanyin Ⅲ, Paspalum vaginatum, Axonopus compressus, Axonopus affinis, Eremochloa ophiuroides and Zoysia matrella. Using stepwise regression analysis, the regression equation was established and five indices (leaf length to width ratio, internode length, chlorophyll a content, chlorophyll b content and POD activity) were selected to evaluate shade tolerance of turfgrass as tolerance significantly influenced these indices thereby simplifying the evaluation process. It was concluded that the mathematical analysis method of using morphological and physiological indices data in the comprehensive evaluation of turfgrass shade tolerance was relatively objective and comprehensive, and can be used in turfgrass resistance studies.

Effects of drought stress on reactive oxygen species and their scavenging systems in Chlorophytum capense var. medio-pictum leaf

JIA Xue-jing, DONG Li-hua, DING Chun-bang, LI Xu, YUAN Ming

2013, 22(5):  248-255.  DOI: 10.11686/cyxb20130529

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The effects of drought stress on reactive oxygen species and their scavenging systems of leaf blade and the center parts of Chlorophytum capense var. medio-pictum were studied. 1) The content of H₂O₂, O₂^-· and MDA gradually increased with the stress time, while the activity of SOD and POD increased in the earlier days, but then declined. 2) The content of reactive oxygen species (H₂O₂ and O₂^-·), activity of scavenging enzymes (SOD and POD) and the content of MDA increased gradually as the PEG concentration increased. 3) The comprehensive evaluation of drought tolerance by the membership function method indicated that there were clear position effects, and drought resistance in the center part of the leaf was stronger than that in the blade of the leaf. 4) Drought resistance was negatively correlated with chlorophyll content: the higher the chlorophyll content, the weaker the drought tolerance. Drought resistance in C. capense var. medio-pictum was better than that of C. capense.

Effect of Hemerocallis root system distribution characteristics on soil nutrients in terrace banks planted for hillslope protection

QIN Chuan, HE Bing-hui, LIU Yong-xin, LI Tian-yang, YAN Li, MA Xi-wu

2013, 22(5):  256-264.  DOI: 10.11686/cyxb20130530

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Terrace banks in the east Sichuan hilly area which were planted with Hemerocallis citrina for slope protection were studied together with soil in bank grids to understand root distribution characteristics and their effect on soil nutrients. Four different planting years of Hemerocallis, were used in field investigations and indoor experiments with a combination of research methods. The differences and relationships between root distribution characteristics, biomass and soil nutrients on terrace banks were analysed. With an increasing age after planting, root length, root volume, root surface area and root volume indexes increased; The root vertical distribution of 4-year-old Hemerocallis were significantly higher than in younger plants. Their values over years one to four were 185.3 cm (17,133 items), 237.5 cm², 301.2 cm³ and 158.9 cm respectively. The root system distribution levels were different due to the restrictions of the grid size. In the four different planting years of Hemerocallis, the average root biomass size sequences were: 4a>3a>2a>1a. There was different growth in different soil layers and also some differences of root biomass. The Hemerocallis root morphology not only affected the growth of the plant itself, but also affected soil fertilization. Root and soil nutrients were higher under three or four years of Hemerocallis than under 1 or 2 years of Hemerocallis, and those index in the bare plots, soil nutrient content were significantly difference between different plant ages in the same soil layer. Total N, available N and available P contents and the Hemerocallis root indicators were significantly correlated. It appears that the Hemerocallis roots have the ability to change the soil nutrients through their soil and water conservation properties. The research results could be used for choosing herbs and improving soil nutrients in the east Sichuan hilly area terrace banks and to provide a theoretical basis and practical reference value.

Differences in root architecture of several Stylosanthes genotypes and their phosphorus efficiency

CUI Hang, LI Li-ying, XIE Xiao-lin, ZHU Hong-hui, YAO Qing

2013, 22(5):  265-271.  DOI: 10.11686/cyxb20130531

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Stylosanthes is an important species for sod culture in orchards in south China. To alleviate nutrient competition by roots between Stylosanthes and fruit trees, it is necessary to screen Stylosanthes genotypes with appropriate root architecture. One experiment was conducted in specially designed rhizoboxes and another in pots. In the first experiment, the root architectures of seven Stylosanthes genotypes were investigated at normal P levels, and in the second experiment, P uptake efficiencies of two Stylosanthes genotypes with contrasting basal root angle were compared. Root architecture was characterized using scanning and WinRhizo analysis. There was a significant difference in root architecture among the seven genotypes. Plant biomass showed significant and positive relationships with total root length, tap root length, and root surface area. Based on plant biomass and root architecture, seven Stylosanthes genotypes were categorized into three classes. Two genotypes (‘Graham’ and ‘CIAT 184’) with high biomass and contrasting basal root angle were chosen for a further comparison of P efficiency. ‘CIAT 184’ had smaller basal root angles and a higher P uptake efficiency at high P level. However, at a low P level, P uptake efficiency was lower leading to a lower P efficiency. This study suggests that basal root angle is an important factor affecting P uptake efficiency, however, P efficiency also depends on plant growth performance at a low P level. ‘Graham’ is probably more suitable for inter-planting in orchards than ‘CIAT 184’.

Effects of flax seed on beef quality and fatty acids in fattening cattle

LI Qiu-feng, XU Lei-lei, LI Jian-guo, CAO Yu-feng, ZHANG Wen-hua

2013, 22(5):  272-279.  DOI: 10.11686/cyxb20130532

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The effects of flax seed on beef quality and fatty acids in fattening cattle was studied in a single-factor design experiment. Thirty two Simmental crossbred beef with similar body weights were assigned to 4 groups with 8 duplicates in each group. The flax seed contents of the concentrates for group Ⅰ(control group), group Ⅱ, group Ⅲ and group Ⅳ were 0%, 5%, 10% and 15% respectively. 1)There were no significant differences in slaughter rate and pure meat percentage between group Ⅳ and the control group; flax seed significantly (P<0.05) increased back fat thickness and fat content of beef: the fat thickness of group Ⅳ increased 57.75% compared with the control group; 2)Adding flax seed to diet reduced shear force and pH value of longissimus at 24 and 48 h post-mortem (P<0.01); 3)Flax seed enhanced polyunsaturated fatty acid (PUFA) content of longissimus fatty acids significantly. These results indicate that increasing flax seed levels of diets can improve carcass quality. Flax seed improved the fatty acid profile, especially by increasing the amounts of PUFA. A comprehensive analysis showed that the optimal feeding level of flaxseed was 10%-15% of concentrate.

Nutritional evaluation of cotton shell and ammoniated cotton shell feed on sheep

ZHAO Sai-chun, ZHENG Chen, LI Fa-di, HAO Zheng-li, LIU Ting, LIU Wei

2013, 22(5):  280-286.  DOI: 10.11686/cyxb20130533

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Four Gansu Alpine sheep (average weight 28 kg) were fitted with permanent rumen fistulas in a 4×4 Latin square design experiment to investigate the nutritional evaluation of cotton shell and ammoniated cotton shell feed on sheep. Digestive energy, the digestibility of dry matter, nitrogen, organic matter, neutral detergent fiber, acid detergent fiber, calcium, phosphorus, N persistence of cotton shell and ammoniated cotton shell were 11.42 and 10.90 MJ/kg, 68.41% and 66.30%, 60.30% and 60.68%, 70.25% and 67.57%, 57.44% and 54.55%, 54.78% and 52.21%, 27.66% and 24.88%, 34.56% and 27.57%, 49.48% and 50.34%, respectively. After feeding cotton shell and ammoniated cotton shell to sheep, there were no significant differences in various digestion rates of nutrient digestibility. There were significant (P<0.05) differences in molar ratio of acetate, propionate, butyrate, other acids, the acetate/propionate ratio, and the concentration of protein nitrogen in ruminal fluid. There were no significant differences in pH, concentration of total volatile fatty acids, total nitrogen, or concentration of urea nitrogen. The nutrient digestibility of cotton shell and ammoniated cotton shell were not significantly different. However, an advantage of the urea ammoniated treatment was that the release of ammonia in the rumen of sheep was faster, and the microbial synthesis was of lower strength in the rumen.

Changes of milk yields and their nutrient composition in confined 0-30 days postpartum sheep

MA You-ji, DONG Qi-li, LI Fa-di, LI Hui, LI Chong, WANG Wei-min, JIANG Zhong-wen

2013, 22(5):  287-293.  DOI: 10.11686/cyxb20130534

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Fourteen ewes of Gansu meat sheep new breeding population were selected to study the milk yield and nutrient composition during 30 days postpartum in this paper. The results showed that the ewes of Gansu meat sheep new breed population had higher lactation performance within 30 days postpartum. The 30 days’ total milk yield was (32.82±0.19) kg, and daily average daily milk yield was (1.09±0.08) kg. The lactation curve equation of 1-30 days was Y=530.60t^0.368e^-0.015t, while daily weight gain reached (0.234±0.033) kg. The milk conventional components and physical properties had significant changes in the first postnatal day, and tended to be steady until the third day. The milk composition differ between colostrums and normal milk, and had certain regularly changes. The content of milk soluble solids, non fat solids, protein and fat decreased, while lactose showed upward trend from the first day to 7th day. The content of milk protein, non fat solids, density and acidity showed a decreasing trend from the first day to 21th day, then rose in the following days. The content of milk fat, soluble solids and acidity had been on a downward trend. while the lactose had upward trend from the first day to 14th day, then its content tends to be steady. The freezing point showed increasing trend from the first day to 5th day, then decreased slowly. The density had no significant changes within 30 days postpartum (P>0.05). The above results have provided the basic data for Gansu meat sheep new breed population’s characteristics and the supplementary feeding of early weaned lambs.

Effect of alfalfa saponins on cholesterol metabolism and its molecular mechanisms

YUAN De-di, SHI Ying-hua, WANG Cheng-zhang, GUO Rui, WANG Jie

2013, 22(5):  294-301.  DOI: 10.11686/cyxb20130535

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To investigate the effects of alfalfa saponins on cholesterol metabolism and its molecular mechanism, 32 healthy male Sprague Dawley (SD) rats were randomly divided into four groups: normal control group, alfalfa saponins group, hyperlipidemia model group, hyperlipidemia model+alfalfa saponins group. The first four weeks were the hyperlipidemia model establishment period: rats in the normal control group and in the alfalfa saponin group were fed with a basal diet while the other two groups were fed with a high fat diet. The last four weeks were the alfalfa saponins treatment period, alfalfa saponins (240 mg/kg) were administrated to both the alfalfa saponin group and to the hyperlipidemia model+alfalfa saponins group by gavage. The body weight, liver index, serum lipid level, total cholesterol and total bile acids in liver and faeces of the rats were measured. The mRNA expression of CYP7a1 and ABCG5/ABCG8 were measured by real-time PCR. Alfalfa saponins significantly reduced the body weight, liver index and the serum cholesterol level but increased the accumulation of cholesterol in liver and the excretion of cholesterol and bile acids in faeces in hyperlipidemia rats and significantly increased the cholesterol excretion in faeces of normal rats. The mRNA expression of CYP7a1 and ABCG5/ABCG8 were multiplied in the alfalfa saponins treated groups. The results indicated that alfalfa saponins could adjust the distribution of cholesterol in rats and had a significant effect on the decrease of serum lipid. This effect could result from the increasing mRNA expression of CYP7a1 and ABCG5/ABCG8 in liver.

Quantitative analysis of the effects of Stipa krylovii and Leymus chinensis on the factors of vitiality of Oedaleus decorus asiaticus

ZHANG Wei-zhong,HE Bing,CAO Guang-chun,ZHANG Ze-hua,WU Ya-han,LIU Shi-chao,WANG Hai-rong

2013, 22(5):  302-309.  DOI: 10.11686/cyxb20130536

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Oedaleus decorus asiaticus, mainly feeding on graminaceous, is one of most harmful grasshopper species in the Inner Mongolia.The effects of plant species on the growth and development of grasshopper reflect relationship between plant communities and grasshopper communities.In this study, by applying both the fields net and indoor independent feeding method, we compared the vitality index of three groups of O. asiaticus with different population densities, and quantitatively analyzed the effect of Stipa krylovii and Leymus chinensis on the growth and development of O. asiaticus. The result indicated that the relative growth rate of female which feed on S. krylovii is higher than which feed on L. chinensis. The plant coverage and the population density are main factors to affect the vitality of O. asiaticus. When the coverage of S. krylovii less than 25%, the vitality value increased slowly with the increase of coverage, when the coverage more than 25%, the vitality value increased rapidly. When the coverage of L. chinensis less than 25%, the vitality value decreased with the increase of coverage,when the coverage more than 25%, the vitality value positively related with the coverage. The vitality of O. asiaticus in S. krylovii is better than in L. chinensis. We also found that when density of grasshopper is less than 18 heads/m², the vitality value increases with the density. When we plant grass should adjust coverage of S. krylovii and L. chinensis, monitor density of O. asiaticus. The results provide an operational base for the rational distribution of grassland and harm reduction of grasshopper.

Mycorrhizal studies and their application prospects in China

LIN Shuang-shuang, SUN Xiang-wei, WANG Xiao-juan, DOU Cun-yan, LI Yuan-yuan, LUO Qiao-yu, SUN Li, JIN Liang

2013, 22(5):  310-325.  DOI: 10.11686/cyxb20130537

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Many papers have been published in the field of mycorrhizal research because of the development of scientific technology and the widespread use of mycorrhizal technology. In this paper, the progress of mycorrhizal studies and their applications in China are reviewed. On the basis of the 1 166 papers published from 2006 to 2010, we analyzed the progress made by Chinese scientists during this period. The main results, including mycorrhizal nutrition, mycorrhizal ecology, use of molecular technology in mycorrhizal studies and the effects of mycorrhizal infection on plant resistance are discussed. The applications of mycorrhiza at the plant nursery stage and in edible fungus production are also discussed. The prospects for mycorrhizal studies and their applications in agricultural and forestry fields in the future are addressed.

Effect of different additives on the quality and nutritional value of bamboo shoot shell silage

WANG Li-sheng, QI Yong-ling, CHEN Fang, LI Da-wei, CHENG Mao-ji

2013, 22(5):  326-332.  DOI: 10.11686/cyxb20130538

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The test researches the quality and nutritional value influence of bamboo shoot shell silage through adding different kinds of silage agent. The test is a total of five groups. Control group (CK), raw materials directly ensiling. Group A: adding corn flour to 10%; Group B: adding corn flour and lactic acid bacteria to (10.000+0.001)%; Group C: adding 0.3% mixed acid (formic acid, acetic acid, propionic acid=80∶11∶9); Group D: adding 3% mixed formic acid and formaldehyde . There are plastic bags for vacuum sealing after 45 days. And they were sampled respectively at silage 3, 5, 8, 15, 23, 30 and 45 days. The experimental results showed that: when bamboo shoot shell single ensiled, the pH value was more than 4.50, NH₃-N to total nitrogen ratio was as high as 22.83% and nutrient was loss of large. Silage effect was not ideal. The test groups respectively adding corn flour, corn flour+lactic acid bacteria, organic acid, formic acid and formaldehyde were that the bamboo shoot shell silage pH value and NH₃-N to total nitrogen ratio were significantly lower than that of control group (P<0.05). Four kinds of additives can significantly improve the content of the crude protein, dry matter and lactic acid (P<0.05), and can make the fermentation quality and the nutritional value of bamboo shoot shell silage improved. Lactic acid content was higher than the acetic acid, propionic acid and butyric acid in all treatments. All the additives could significantly increase the content of lactic acid and decrease acetic acid, propionic acid and butyric acid content (P<0.05). The order of each treatment group excellence was B>A>D>C>CK on silage quality and nutritional value. That is an important period of silage quality and nutritional value before ensiling 8 days.

Nutrient assimilating capacity of Lolium multiflorum pasture for dairy farm biogas slurry

YIN Ya-li, XING Xue-feng, TANG Hua, LI Zhi-yan, LIU Ming-xiu, XU Hui-zhong, GUO Yan-jun

2013, 22(5):  339-344.  DOI: 10.11686/cyxb20130540

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Four sampling points from Jiayuguan, Gansu province were investigated to determine the pathogen, pathogenicity, and dominant population of onion basal plate rot disease. Based on morphological and cultural characters the disease pathogens were identificated as Fusarium oxysporum, F. solani and F. moniliforme. The dominant species was F. oxysporum and although pathogenicity testing showed that the three species could cause onion basal plate rot disease, F. oxysporum had the strongest pathogenicity and its disease rate and disease index reached 84.4% and 65.3, respectively. Compared with the other fungi, there was a significant difference. Laboratory toxicity tests of four fungicides to the mycelial growth of the three species showed that 200 μg/L of the Shijunke fungicide had the strongest activity. 

Diversity of ground-dwelling beetles at the edge of grassland and artificial Caragana fields in Sidunzi, Yanchi County, Northwest China

JIA Yan-xia, WANG Xin-pu

2013, 22(5):  345-350.  DOI: 10.11686/cyxb20130541

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The influences of edge effects on ground-dwelling beetles (Coleoptera) across an artificial Caragana intermedia-grassland ecotone were investigated. The study was conducted in Sidunzi, Yanchi County, Ningxia, Northwest China. During the field research, a total of 1 101 beetles belonging to 13 families were collected with pitfall traps. Of these beetles, Carabidae (17 species) and Tenebrionidae (12 species) were the most abundant species. Four families dominated: Tenebrionidae, Carabidae, Scarabaeidae and Melolonthidae which accounted for 41.78%, 10.81%, 10.54% and 10.45% of the total, respectively. From artificial Caragana intermedia to the edge and then to grassland, family abundance, diversity and evenness decreased in sequence, and were significantly different between the three habitat types. Edge effect intensity on diversity of ecotone was above 1 (1.039 6), and had a positive effect.