Table of Content

20 June 2019, Volume 28 Issue 6

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GIS-based analysis of the compatibility of two grassland classification systems in China

LIU Xiao-ni, ZHANG De-gang, WANG Hong-xia, REN Zheng-chao, HAN Tian-hu, SUN Bin, PAN Dong-rong, WANG Bo

2019, 28(6):  1-18.  DOI: 10.11686/cyxb2018337

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The qualitative vegetation-habitat classification system (VHCS) and the quantitative comprehensive and sequential classification system (CSCS) are the two major grassland classification systems in China. However, the use in practice of the classification results from these two systems has been difficult due to the different approaches (qualitative vs quantitative) and grassland definitions adopted by the two systems, causing difficulties in comparing the grassland types classified from these two systems. Through overlaying the CSCS classification map and the digitized VHCS map in ArcGIS for the grasslands in Inner Mongolia Autonomous Region and Gansu Province, this study compared the criterion and characteristics of the two systems at the first classification level (class), analyzed their compatibility and developed the corresponding relationships to translate the types between two systems. The results show: 1) CSCS is generally compatible with VHCS when comparing the broad grassland types (class); 2) at the class level, the VHCS and CSCS system are generally in agreement when comparing the class names, characteristics and parameters used; 3) if not considering forest and non-zoning classes, the results of the spatial overly indicated that the compatibility of two systems can be as high as 61.4% and 61.1% for Inner Mongolia and Gansu, respectively. The areas where the grassland classes from the two systems were different were mainly degraded from the potential natural vegetation (as classified by CSCS) and were observed as classes in the VHCS system as low-level grassland under more severe climate conditions. This indicates that the human disturbance has surpassed the survival thresholds of these potential natural grassland vegetation categories, resulting in retrogressive succession of the grasslands; 4) the results from the comparative analyses of the CSCS and VHCS systems provided insight into the succession mechanisms of grassland ecosystems under human disturbance, and are helpful in grassland management with regard to system restoration and reestablishment.

Spatio-temporal dynamic changes of grassland NPP in Gannan prefecture, as determined by the CASA model

LIU Jie, MENG Bao-ping, GE Jing, GAO Jin-long, YIN Jian-peng, HOU Meng-jing, FENG Qi-sheng, LIANG Tian-gang

2019, 28(6):  19-32.  DOI: 10.11686/cyxb2018320

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Net primary productivity (NPP) plays an important role in global carbon cycle and is important to understanding drivers of climate changes. Precise and rapid estimation of vegetation NPP is important for evaluating ecological carrying capacity at a regional scale and managing natural resources reasonably. In this study, field-measured grassland above ground biomass (AGB) from 2011 to 2014, MODIS remote sensing data and meteorological data in Gannan prefecture were used. In combination with the ratio of belowground biomass to AGB, we calculate the grassland NPP, and evaluate the accuracy of the MOD17A3 product and Carnegie-Ames-Stanford approach (CASA) model, and analyze the dynamic changes of grassland NPP from 2000 to 2016 using the better method. The results show that the accuracy of grassland NPP predictions from the CASA model (root mean square error (RMSE) = 9.94 g C ·m^-2·yr^-1) is higher than that of MOD17A3 product. The average annual grassland NPP determined by the CASA model shows a decreasing trend from the southwest to northeast between 2000 and 2016 in our study area. Comparing different vegetation types, the annual NPP for marsh grassland (469.07 g C ·m^-2·yr^-1) was the highest, while that of temperate steppe grassland was the lowest (324.18 g C ·m^-2·yr^-1). In addition, the annual NPP of alpine meadow and alpine shrub meadow grasslands (which have relatively large area in Gannan prefecture) was, respectively, 370 and 430 g C ·m^-2·yr^-1. Over the past 17 years, the annual grassland NPP was generally stable in most regions, (75.31% of the total grassland area). Meanwhile, an increasing NPP trend was seen in 22.63%, and a decreasing trend in just 2.06% of the Gannan prefecture area. These results suggest that the CASA model has an important role in grassland NPP estimation and will assist in the sustainable management of grassland resources in alpine areas.

Effect of different vegetation planting patterns in restoration of degraded sandy land in northwest Sichuan

GOU Xiao-lin, LIU Wen-hui, CHEN You-jun, ZHOU Rong, ZHOU Qing-ping

2019, 28(6):  33-44.  DOI: 10.11686/cyxb2018398

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Establishment of vegetation for sand stabilization is a widely used technique in restoration of desertified land, and little research has been conducted into the effects of different planting patterns on restoration outcomes. In particular, few studies have examined different planting patterns for composite grass-sand barriers for restoration in alpine-cold desert regions. In this study, typical alpine sub-humid sandy land in the northwest of Sichuan was planted in 2014 in three patterns (row planted, band planted, or scatter planted) with a mixture of three grasses: Avena sativa, Elymus nutans and Festuca sinensis. Data were collected in August 2014 on the growth of A. sativa, and again in August, 2017 to check plant community, coverage, biodiversity and collect soil samples. Soil water content, bulk density, pH value, organic carbon, total nitrogen, total phosphate, ammonia nitrogen, nitrate nitrogen and available phosphate were determined by standard laboratory techniques. Results showed that band and scatter planting patterns had significant positive effects on restoration of sub-humid sandy land. The annual species A. sativa had disappeared from the ecosystem by 2017, and the two perennial grasses grown well. The band and scatter planting patterns showed significantly superior plant coverage, biodiversity and ecosystem development, together with decreased soil bulk density, but increased soil water content, organic carbon, total nitrogen, total phosphate and other benefits. For sub-humid alpine sandy land restoration using grass mixtures, we suggest soil bulk density, organic carbon and total nitrogen are useful indexes of soil improvement. Also we recommend use of grass mixtures in band or scatter planting patterns as a suitable technique for restoration of desertified alpine land, to both restore vegetation cover above ground, and improve soil properties below ground.

Effects of additional KCl on growth and physiological characteristics of sainfoin (Onobrychis viciaefoia) under high salt stress

WU Guo-qiang, LI Hui, LEI Cai-rong, LIN Li-yuan, JIN Juan, LI Shan-jia

2019, 28(6):  45-55.  DOI: 10.11686/cyxb2019015

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To investigate the effects of K⁺ on the growth and relevant physiological parameters in sainfoin (Onobrychis viciaefoia) under high-salt stress, in this study, 4-week-old seedlings, with or without 100 mmol·L^-1 NaCl (high-salt stress), were subjected to various concentrations (5, 10, 25 and 50 mmol·L^-1) of KCl for 7 days, in this study. It was found that high-salt stress significantly inhibited the growth of sainfoin seedlings compared to the control. However, the addition of different concentrations of KCl clearly ameliorated the inhibition of high-salt stress on growth of seedlings. Under high-salt stress, with increasing KCl concentration, fresh weight, dry weight, tissue water and total chlorophyll contents showed a trend of gradual increase, reaching their greatest values when KCl concentration was 25 mmol·L^-1, while Na⁺ concentrations in both shoots and roots displayed a gradual reduction, but K⁺ concentrations and K⁺/Na⁺ ratios, remarkably, displayed an increasing trend. Proline, soluble sugar and soluble protein contents also reached their peak values when concentration of KCl was 25 mmol·L^-1, and were a little lower at 50 mmol·L^-1 KCl concentration. Malondialdehyde content, and cell wall, cytoplasmic and vacuolar invertase activities exhibited clearly decreasing trends, while superoxide dismutase, catalase, ascorbate peroxidase, sucrose synthase and sucrose phosphate synthase activities, together with sucrose and glucose contents, showed gradually increasing trends. Taken together, our results suggested that the addition of K⁺ alleviates high-salt toxicity to sainfoin seedlings by maintaining K⁺ and Na⁺ homeostasis, enhancing antioxidant enzyme activities, and improving sucrose synthesis and accumulation in shoots.

Molecular cloning, transcriptional activation, subcellular localization analysis and expression characterization of ZjERF1 from Zoysia japonica

TENG Ke, ZHANG Rui, TAN Peng-hui, YUE Yue-sen, FAN Xi-feng, WU Ju-ying

2019, 28(6):  56-65.  DOI: 10.11686/cyxb2018323

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The ERF transcription factors (TFs) are one of the largest groups in plants and play important roles in plant developmental progress and responses to abiotic stresses. In this study, one novel ERF gene, ZjERF1 (GenBank No. MH294481), was isolated from Zoysia japonica using the RACE method. The open reading frame of ZjERF1 is 630 bp in length, encoding 209 amino acids. One highly conserved AP2 domain was found in ZjERF1, indicating ZjERF1 was a typical ERF TF. By genome walking, a 1581 bp upstream sequence from the ATG of ZjERF1 was obtained. Bioinformatics analysis revealed that there were several cis-elements in response to MeJA and abiotic stresses in the promoter. To investigate the transcriptional activation character, a pGBKT7-ZjERF1 vector was constructed and then was transformed into Y2HGold yeast cells; the results showed that ZjERF1 had strong transcriptional activity. To reveal the subcellular localization character, 35S::ZjERF1:YFP was generated. The transient expression analysis in Nicotiana benthamiana demonstrated that ZjERF1 was localized in the nucleus. To further explore the expression characteristics, real-time quantitative PCR was carried out. The results showed that ZjERF1 was expressed most abundantly in the stem and its transcriptional abundance was positively correlated with leaf senescence. Moreover, its expression could be induced by 200 μmol·L^-1 ET, 10 μmol·L^-1 MeJA or 300 mmol·L^-1 NaCl but was suppressed by 20% PEG4000. Taken together, these findings proves that ZjERF1 is a functional TF involved in various signaling pathways and paves the way for further study of the function of ZjERF1 and its regulatory mechanism in Z. japonica.

Effects of different heavy metals on the seed germination and establishment of Halogeton glomeratus

HU Na, LI Bao-chun, YAO Li-rong, WANG Jun-cheng, BIAN Xiu-xiu, HOU Jing-jing, SI Er-jing, YANG Ke, MENG Ya-xiong, MA Xiao-le, WANG Hua-jun

2019, 28(6):  66-81.  DOI: 10.11686/cyxb2019012

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In order to better understand the tolerance of halophyte Halogeton glomeratus to different heavy metals, this research focused on its seed germination and seedling growth when exposed to different heavy metal stresses. Indicators of seed germination and seedling growth, including the germination percentage, germination energy, plant height, fresh weight, dry weight, root activity and ion content of H. glomeratus seeds treated with five major soil heavy metal pollutants (Cu, Zn, Ni, Cd, Pb), were measured and data analysed by cluster and principal component analyses. It was found that lower concentrations of the five different heavy metals had little effect on seed germination, while higher concentrations had an inhibitory effect. However, the effects on seedling growth index were different. The plant height, fresh weight and root activity showed no significant difference under the lower concentrations of Zn²⁺ and Pb²⁺, but showed a significant decrease under the lower concentrations of Cu²⁺, Ni²⁺ and Cd²⁺.Especially, the decrease was most obvious at 5.00 mmol·L^-1 Zn²⁺, 3.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.20 mmol·L^-1 Cd²⁺, and which is the lowest concentration of inhibition effect. The plant height, fresh weight, dry weight, root activity and ion content were lower than the control under the concentration of 5.00 mmol·L^-1 Zn²⁺, all of them showing a decrease to 55%, and which showed a decrease to 52%, 40%, 46% and 53% of the control for 3.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.20 mmol·L^-1 Cd²⁺, respectively. Furthermore, the ion contents of the plant tissue increased with increase in heavy metal concentrations, and these increases first became obvious at 5.00 mmol·L^-1 Zn²⁺, 3.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.20 mmol·L^-1 Cd²⁺. On cluster analysis, the metal stress concentrations were clustered into two categories based on 3.00 mmol·L^-1 Zn²⁺, 1.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.10 mmol·L^-1 Cd²⁺, respectively. In addition, the principal component analysis showed that germination indices are mainly affected by Zn²⁺(PCA 1), Pb²⁺ (PCA 1) and Ni²⁺(PCA 1+PCA 2) treatments, and biomass has most affected by the Cu²⁺(PCA 1+PCA 2) and Cd²⁺(PCA 1+PCA 2)treatments.These results indicated that there was little effect on seed germination and seedling growth of H. glomeratus while the heavy metal concentrations were lower than 3.00 mmol·L^-1 Zn²⁺, 1.00 mmol·L^-1 Pb²⁺, Cu²⁺, Ni²⁺ and 0.10 mmol·L^-1 Cd²⁺. The germination indexes can be used for evaluating the tolerance of H. glomeratus to Zn²⁺, Pb²⁺ and Ni²⁺ during the germination period, and biomass can be used to evaluate the tolerance of H. glomeratus to Cu²⁺ and Cd²⁺.

Comparison of production performance and winter survival rate of different fall dormancy alfalfa varieties

WANG Xiao-long, LI Hong, MI Fu-gui, YU Jie, WANG Xue-ting, MENG Kai, JIA Zhen-yu, WANG Quan-zhen

2019, 28(6):  82-92.  DOI: 10.11686/cyxb2018335

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Selection for fall dormancy in alfalfa can impact other traits such as hay yield, nutritive value, re-growth rate, stem leaf ratio, plant height and winter survival rate. The objective of this study was to identify the optimum alfalfa varieties for cultivation in Hohhot area. A total of eight alfalfa varieties (Caoyuan No.3, Zhongmu No.2, Caribou, Gold empress, Sanditi, Sardi, WL525, WL903) were planted in a regional test field. The experiment used a randomized block design and the eight cultivars were mowed at the early flowering stage in 2015, 2016, and 2017. In order to select the optimal alfalfa varieties, forage yield and nutrient composition, including dry matter (DM), crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF) were determined and the relative feed value (RFV) was calculated. The results showed that the winter survival rate of Zhongmu No.2, Caoyuan No.3, and Caribou all exceeded 95%. Together with Gold empress, the four varieties had significantly higher survival rates than the others (P<0.05). In addition, there was a significant negative correlation between fall dormancy and winter survival rate (-0.984; P<0.01). However, there was no significant correlation between fall dormancy and hay yield (P>0.05). The highest hay yield was obtained from Zhongmu No.2 in 2015. The hay yield of Zhongmu No.2 and Gold empress were significantly higher than the other varieties (P<0.05) and Caribou and WL525 had a relative low yield in 2016. In 2017, the top three varieties in hay yield were Zhongmu No.2, Gold empress and Caoyuan No.3. Moreover, the crude protein content of Caoyuan No.3 and Zhongmu No.2 were both greater than 20%. And Zhongmu No.2 had the lowest acid detergent fiber and neutral detergent fiber contents, as well as the highest relative feed value. According to subordinate function value analysis, Zhongmu No.2, Gold empress and Caoyuan No.3 were the optimum alfalfa varieties. In summary, fall dormancy of alfalfa had no significant effect on alfalfa production performance such as hay yield and nutritive value, but was significantly negative correlated with winter survival rate. Our study showed that Zhongmu No.2, Gold empress and Caoyuan No.3 had greater performance than the others in hay yield, winter surviving and nutrition quality, and they were the optimum alfalfa varieties for planting in Hohhot area of Inner Mongolia.

Effect of plant growth regulator on seed yield of Dactylis glomerata

ZHANG Xu, NIE Gang, HUANG Lin-kai, TANG Lu, ZHOU Zhou, LIU Fu, ZHOU Jie, ZOU Jing, REN Si-yan, ZHANG Xin-quan

2019, 28(6):  93-100.  DOI: 10.11686/cyxb2018729

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The testing of plant growth regulator (PGR) yielded new insight to improve the seed yield of forage crops. In this study, two PGRs [chlorocholine chloride (CCC): 500, 750, 1000, and 1250 g·ha^-1; trinexapac-ethyl (TE): 100, 200, 300, and 400 g·ha^-1] and their mixtures (500+50, 500+150, 1000+50, 1000+150, 1000+150, 1000+150 g·ha^-1) were applied to Dactylis glomerata to evaluate the effect on the seed yield over two years of field trials. The results showed that both growth regulators and their mixtures used in this study increased the seed yield of D.actylis glomerata. The mixture of CCC+TE (500+150 g·ha^-1) resulted in the largest seed yield, which was an increase of 46.2% compared to control plots (without any PGR treatment). The main mechanism for action of the PGR was to increase the fertile tillers per unit area and seed setting rate in the field. The use of PGR had no significant effect on seed weight or on floret number per spike.

Effects of endophytic Bacillus subtilis 265ZY4 on physiological and biochemical characteristics of Stipa purpurea under abiotic stress

YANG Cheng-de, CUI Yue-zhen, FENG Zhong-hong, XUE Li, JIN Meng-jun

2019, 28(6):  101-108.  DOI: 10.11686/cyxb2018342

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In order to understand the effects of the endophytic bacterium, Bacillus subtilis, on Stipa purpurea under high temperature, low temperature and ultraviolet stress, the biochemical characteristics of S. purpurea inoculated with B. subtilis strain 265ZY4 were compared with those of plants not carrying the bacterial endophyte. The results showed that the height and leaf width of S. purpurea with 265ZY4 were 35.02% and 34.69%, respectively, more than in the control plants. When S. purpurea was subject to high- or low-temperature stress, leaf chlorophyll content rose and then fell. Under ultraviolet stress, chlorophyll levels dropped rapidly, but the chlorophyll content of S. purpurea with 265ZY4 remained higher than those in the control. The soluble protein and soluble sugar levels also initially rose and then dropped under abiotic stress, but the soluble sugar levels of S. purpurea with 265ZY4 were distinctly higher than those in the control plants after 4 and 6 days. The superoxide dismutase (SOD) activity displayed a decrease-increase-decrease curve with progressive increase in high- and low-temperature stress, but the SOD activity of S. purpurea with 265ZY4 was more stable. The SOD activity of the control plants showed a decrease-increase-decrease curve pattern under increasing ultraviolet exposure, but the activity of S. purpurea with 265ZY4 showed a curve pattern that differed from the control plants. The phenylalnine ammonialyase (PAL) activity displayed an increase-decrease curve pattern under low temperature stress and a decrease-increase-decrease curve under high temperature and ultraviolet stress, but the PAL activities of S. purpurea plants with 265ZY4 were distinctly higher than those in the control. In summary, the results show that the endophytic B. subtilis strain 265ZY4 is beneficial to S. pupurea through assisting with maintenance of chlorophyll, soluble protein, and soluble sugar levels, and SOD and PAL activities, and reducing the range of metabolic variability under the abiotic stress factors tested, thus indicating enhancement of S. purpurea stress tolerance ability.

Effects of Lactobacillus plantarum (LP) and moisture on feed quality and tannin content of Moringa oleifera leaf silage

WANG Cheng, WANG Yi, ZHOU Wei, PIAN Rui-qi, ZHANG Qing, CHEN Xiao-yang

2019, 28(6):  109-118.  DOI: 10.11686/cyxb2018339

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This study aimed to investigate the effect of moisture and Lactobacillus plantarum (LP) on the quality and tannin content of Moringa oleifera leaf silage. The design was a completely randomized, two-factor (60%, 70%, or 75% moisture×+/- LP, 1×10⁶ cfu·g^-1 fresh matter. After 60 and 120 days ensiling, samples were collected to determine fermentation quality, protein composition and tannin content. The M. oleifera leaves at ensiling had a crude protein (CP) content of 16.72% of dry matter (DM), and water soluble carbohydrate (WSC) content of 10.72% DM. The moisture content had a significant effect on the quality of M. oleifera leaf silage. Compared with the 60% water group, the content of ammoniacal nitrogen (NH₃-N) and free amino acid (FAA) in the 70% water content group was significantly decreased (P<0.05), and the contents of lactic acid (LA), acetic acid (AA) and propionic acid (PA) were significantly increased (P<0.05). At 70% water content, adding L. plantarum resulted in significantly increased (P<0.05) the content of organic acids (LA, AA, PA), while the numbers of lactic acid bacteria and yeasts were significantly decreased (P<0.05). After 60 d at 75% moisture content, the addition of L. plantarum had reduced the pH value significantly (P<0.05), and all treated coliform counts were less than 2.0 log cfu·g^-1 fresh matter. None of the various combinations of LP and moisture treatment produced any statistically significant change to the tannin content of M. oleifera leaf silage (P>0.05). The protein content of M. oleifera leaves is high, and they are easy to ensile. The 70% water content and the addition of LP obviously improve the quality of M. oleifera leaf silage, but do not have any significant effect on degradation of the tannin content.

Effects of single and multiple inoculants on Hemarthria compressa silage quality

LI Xiao-ling, GUAN Hao, SHUAI Yang, LI Xiao-mei, PENG An-qi, LI Chang-hua, PU Qi, YAN Yan-hong, ZHANG Xin-quan

2019, 28(6):  119-127.  DOI: 10.11686/cyxb2018349

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In order to improve the silage quality of Hemarthria compressa in hot and humid areas, three selected lactic acid bacteria strains [Pediococcus pentosaceus (PP04), Weissella cibaria (WC10) and Lactobacillus plantarum (LP694)] were used as single or multiple additives during H. compressa silage preparation. The treatments tested were as follows: 1) PP04 (Pediococcus pentosaceus); 2) WC10 (Weissella cibaria); 3) LP694 (Lactobacillus plantarum); 4) M-1 [PP04 (Pediococcus pentosaceus):WC10 (Weissella cibaria)=2:1]; 5) M-2 [PP04 (Pediococcus pentosaceus):LP694 (Lactobacillus plantarum)=1:2]; 6) M-3 [WC10 (Weissella cibaria):LP694 (Lactobacillus plantarum)=2:1]; 7) M-4 [PP04 (Pediococcus pentosaceus):WC10 (Weissella cibaria):LP694 (Lactobacillus plantarum)=2:1:1]; 8) CK (uninoculated control). The ratio of NH₃-N/TN in the inoculant treated groups was significantly lower than in the control group (P<0.05), while lactic acid bacteria (LAB) treated silages had higher lactic acid content, dry matter content and recovery of dry matter than the uninoculated control (P<0.05). The pH value of all treated groups was less than 4.2, and the lowest pH value (3.86) was observed in the M-4 treatment formulation. Furthermore, the M-4 treatment group had the highest lactic acid content and lowest NH₃-N/TN ratio (P<0.05). Generally, inoculation with one or multiple strains of lactic acid bacteria was beneficial and enhanced the quality of H. compressa silage. The optimal formulation among those tested, for preparing H. compressa silage, was M-4 (PP04:WC10:LP694=2:1:1).

Effects of homo-and heterofermentative lactic acid bacteria on the nutritional quality and ruminal degradation rate of the whole plant maize silage

LI Fei-fei, ZHANG Fan-fan, WANG Xu-zhe, MIAO Fang, MA Chun-hui

2019, 28(6):  128-136.  DOI: 10.11686/cyxb2018354

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In this study, whole plant maize silage (cv. ‘Xingsiyu No.10’) was sealed in vacuum bags, with the addition of different lactic acid bacteria (LAB) to aid fermentation. Treatments were: CK, untreated maize silage with no inoculant applied; T, maize silage treated with Lactobacillus plantarum+Pediococcus acidilactici at 1:1, 1×10⁵ cfu·g^-1; Y, maize silage treated with Lactobacillus buchneri at 1×10⁵ cfu·g^-1; TY, maize silage treated with combined Lactobacillus plantarum, Pediococcus acidilactici and Lactobacillus buchneri 1:1:1, 1×10⁵ cfu·g^-1. The purpose was to explore the effect of homo- and heterofermentative LAB on nutritional quality and ruminant actual utilization efficiency of maize silage. The silage nutritional quality and digestibility in the rumen was tested by feeding to sheep after 60 days of fermentation. Treatment-Y was highest for dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), water soluble carbohydrates and ether extract levels. Maize silage treated with LAB had higher (P<0.01) crude protein and starch than the untreated CK silage. The untreated maize silage had the highest crude ash content. The comparative effective degradation (ED) in the sheep rumen for DM and NDF was T and Y>CK and TY (P<0.01). Treatment Y also had the highest ED in-rumen for organic matter (OM) (P=0.003). There was no significant difference between treatments in ED of ADF (P>0.05). In conclusion, treatment-Y significantly improved the nutrient content of maize silage (except for crude ash), as well as the ED in the sheep rumen of DM and OM. Treatment-TY significantly improved ED in the sheep rumen of NDF. The overall nutritive value of the 4 maize silage treatments ranked Y>T>TY>CK, as determined by membership function analysis of 12 measures of nutritional quality and ED.

Evaluation using a gas production technique in vitro of associative effects on digestibility of corn cob, alfalfa and concentrate in mixed rations

TANG De-fu, YUAN Jiu, WANG Yan-qian, WANG Yan-na, WANG Juan-li, LIU Zi-qiang, KOU Wei, CUI Zhong-yong, ZHANG Ze-yan, ZHAO Xiang-min, WAN Xin-jie

2019, 28(6):  137-147.  DOI: 10.11686/cyxb2018826

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This experiment was conducted to investigate, using an in vitro gas production (GP) technique, the associative effect (AE) when corn cob (CC) was added as a supplement to an alfalfa (A) and commercial concentrate (C) feed mix. A series of rations was formulated with concentrate-roughage ratio (C:R) of either 40:60 (n=5), or 30:70 (n=6). Specifically, the C:CC:A ratios for the 11 ration formulations tested were: 40:60:0, 40:45:15, 40:30:30, 40:15:45, 40:0:60, 30:70:0, 30:55:15, 30:40:30, 30:25:45, 30:10:60 and 30:0:70. Gas production (GP) was recorded at 0, 2, 4, 6, 9, 12, 24, 36, 48 h. After incubation, the incubation fluid and residues were used to determine pH, volatile fatty acids (VFA), ammonia nitrogen (NH₃-N), dry matter digestibility (DMD) and organic matter digestibility (OMD). The single factor AE index (SFAEI) was defined as the difference between the observed value and the predicted value for an individual feed fermented alone. Also, the multiple-factor AE indexes (MFAEI) of the 11 rations were calculated. It was found that when C:R was 40:60 those rations with 15% or 30% CC had a higher GP, DMD, OMD, NH₃-N, and TVFA, as well as higher SFAEI of GP, DMD, OMD, NH₃-N, and total VFA (P<0.05 or P<0.01). When C:R was 30:70, then rations with 10%, 25%, 40%, or 55% CC generally performed well. Meanwhile, the ration formulations C:CC:A of 40:30:30 and 30:10:60 had a significantly higher MFAEI (P<0.01) than other rations. It was therefore concluded that the greatest AE occurred when C:CC:A ratios were 40:30:30 and 30:10:60.

Variety effects on fermentation quality and nutritive value of whole-plant maize silage

LIU Yue, WANG Guo-gen, WU Hao, MENG Qing-xiang, SONG En-liang, CHENG Hai-jian, ZHOU Zhen-ming

2019, 28(6):  148-156.  DOI: 10.11686/cyxb2018809

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This experiment was conducted to investigate the fermentation quality and nutritive value of whole-plant maize silage made from different silage-specific varieties. Zheng Silage No.1, Jinling Silage No.17 and Jingke Silage No.516 were harvested at one-half to three-fourths milk line and ensiled in plastic bags (50 cm×80 cm) for 60 days, then sensory evaluation was performed and fermentation quality analyzed. Chemical composition and in vitro digestibility were carried out after air-drying of samples. All varieties performed well in the sensory evaluations, while the grain content and total score showed significantly differences among varieties (P<0.01), color and odor also differed (P<0.05). There were significantly differences in fermentation parameters among varieties (P<0.01), and when Flieg score (FS) was ≥ 110.00 points, fermentation quality was excellent. There were significantly differences among varieties in dry matter (DM), crude protein (CP), ether extract (EE), water soluble carbohydrate (WSC), starch, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), ash contents and relative feed value (RFV) (P<0.01), and RFV was >121.00 in all cases. There were also significantly differences in silage yield and energy values among varieties (P<0.01). The milk per ton index (MT), total digestible nutrients (TDN) and energy values of Zheng Silage No.1 were significantly higher (P<0.01), while DM yield and milk per acre index (MA) were significantly lower than other two varieties (P<0.01). The dry matter (DM) yield of Jinling Silage No.17 was significantly higher (P<0.01), MT, TDN and energy values were significantly higher than Jingke Silage No.516 (P<0.01), and milk per acre index (MA) was the highest. Carbohydrate fractions analysis, in vitro DM digestibility (IVDMD) and in vitro NDF digestibility (IVNDFD) showed significantly differences among varieties (P<0.01). The IVDMD and IVNDFD of Jinling Silage No.17 were significantly higher than other tested varieties (P<0.01). The IVDMD of Jingke Silage No.516 was significantly higher than Zheng Silage No.1 (P<0.01), while the IVNDFD of Zheng Silage No.1 was significantly higher than Jingke Silage No.516 (P<0.01). In conclusion, Jinling Silage No.17 performed better than the other two varieties in this experiment, and the second ranked performer was Jingke Silage No.516.

Studies of the flowering habits and pollination for diploid Isatis indigotica

ZHANG Jin-xia, CHEN Yuan, GUO Feng-xia, WANG Yin-quan, ZHOU Sheng-mao, XIAO Sheng-wei

2019, 28(6):  157-166.  DOI: 10.11686/cyxb2019022

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Isatis indigotica is the primary ingredient of traditional Chinese drugs ‘Banlangen’ and ‘Daqingye’, and its cultivation relies on seed propagation. This research examined the flowering habit and pollination biology of I. indigotica cultivated in Minle county. The work included field observation and an artificial pollination experiment, in order to provide scientific and technical information to support seed production and heterosis utilization in this crop. It was found that the plant had an infinite inflorescence consisting of an upright main stem bearing raceme-like branches with new branches above as older matured branches below and 10-20 individual flowers per branch opening in an acropetal sequence over a flowering period of some 30 days. Flowers are bisexual with 6 stamens, four of which are long and two of which are short. There are 4 green calyces, 4 yellow petals with ovary superior, and 1 locule. The flower lifespan was 6-7 days but was shortened to 3-4 days under adverse climate conditions. The stigma matures just prior to the flowers opening. When the petals are just emerging from the calyx tube, bright fresh yellow pollen grains become visible and are dispersed by the flowering day. Anthers then begin to wither, and the ovary expands at the end of the flowering stage, growing a short pod with 0-2 seeds. Seed set was 95.0% for plants under natural conditions. Under covered conditions with paper bags, seed set was very low (approximately 4%) both with and without castration, but was 72.0% when plants were cross-pollinated after castration. When plants were cross-pollinated after castration, but the inflorescence was unbagged, seed set was 53.3%. The self-incompatibility index was assessed as 0.96-1.00. For bagged racemes, seed set was 5.0% without castration and increased to 13.7% after castration. The most common flower pollinator visitors were Episyrphus balteatus and Apis mellifer but various other insect species also visited. These results indicate that I. indigotica has strong self-incompatibility without apomixis, and can be considered a typical cross-pollinating plants needing pollinators, pollinated mainly by insects but supplemented by wind.

Gut hormone release and appetite responses to L-Arg in rats

WANG Chao, KANG Cui-cui, FENG Jiang-yin, XIAN Yi-han, YU De-fu, ZHU Wei-yun, HANG Su-qin

2019, 28(6):  167-174.  DOI: 10.11686/cyxb2018319

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The objective of this study was to investigate the effects of L-arginine on feed intake, gastrointestinal hormone secretion and gene expression of calcium-sensing receptors (CaSR) in rats. Two experiments were conducted. In experiment I, thirty-two male Sprague-Dawley (SD) rats were randomly divided into 4 groups: a control group (oral gavage 0 mmol·kg^-1 L-Arg·HCl), a low dose group (5 mmol·kg^-1 L-Arg·HCl), a medium dose group (10 mmol·kg^-1 L-Arg·HCl) and a high dose group (20 mmol·kg^-1 L-Arg·HCl). The feed intake was recorded at different time points after gavage, and the indicated dose of L-Arg·HCl was chosen for the experiment II based on feed intake. In experiment II, thirty male rats were divided into two groups: a L-Arg·HCl treatment group (20 mmol·kg^-1) and a control group (0 mmol·kg^-1). The corresponding solution was gavaged once a day consecutively for one week. During this period, daily feed intake and changes in body weight were recorded. At the end of the experiment, all rats were euthanased. The venous blood, stomach and small intestine tissue, and hypothalamus were collected for the analysis of gastrointestinal hormones, and gene expression of the CaSR, neuropeptide Y and proopiomelanocortin (POMC) levels. In experiment I, compared with the control group, the concentrations of L-Arg·HCl at 10 and 20 mmol·kg^-1 reduced food intake for 0-1 and 0-24 h, respectively, after gavage (P<0.05), with the greatest reduction in feed intake occurring at 20 mmol·kg^-1. In experiment II, after being orally gavaged with 20 mmol·kg^-1 L-Arg·HCl for 1 week, the body weight gain and cumulative feed intake in the first two days were decreased (P<0.05), while the secretion of cholecystokinin (CCK), expression of CaSR and POMC were up-regulated (P<0.05). However, the secretion of gastrin and glucose-dependent insulinotropic peptide (GIP) was not significantly affected, but did show an increasing trend. A correlation analysis suggested that the concentration of CCK in serum had a significant positive correlation with the gene expression level of CaSR in the duodenum, jejunum and with hypothalamic POMC (P<0.05), while the concentration of GIP in serum had a positive correlation with the expression level of CaSR in the duodenum and POMC in the hypothalamus (P<0.05). Meanwhile, the concentration of glucagon-like peptide-1 in serum displayed a trend towards positive correlation with the gene expression level of CaSR in jejunum and POMC in the hypothalamus (0.05<P<0.1). These results suggest that L-Arg may reduce feed intake of rats by up-regulating the expression of CaSR, increasing the secretion of gut satiety hormones, and up-regulating the expression of the anorexia factor POMC.

Effects of alfalfa meal and alfalfa flavonoids on colon microflora of weaned piglets

QU Gen, LIU Jian-yu, GUO Zhi-peng, WANG Miao-li, GUAN Yong-zhuo, ZHANG Jing-xue, GUO Yu-xia, YAN Xue-bing, ZHANG Ming

2019, 28(6):  175-184.  DOI: 10.11686/cyxb2018338

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This experiment was conducted to investigate the effects of alfalfa meal and alfalfa flavonoids on colon microflora of weaned piglets. In this experiment, 120 weaned piglets (Duroc×Landrace×Yorkshire) of similar weight and parity, and aged (35±1) days were randomly divided into 5 groups with 3 replicates per group and 8 piglets per replicate. A control group was fed a basal diet and experimental groups were supplemented with 1 (group Ⅰ), 2 (group Ⅱ), or 4 (group Ⅲ) g·kg^-1 alfalfa flavonoids and 50 (group Ⅳ) g·kg^-1 alfalfa meal per kilo added to the basal diet. A pre-experiment feed-adjustment period of 3 d was provided, and the experiment lasted for 32 days. On the final day of the experiment, colonic contents were collected. Total bacterial DNA was extracted from the colonic contents and 16S rDNA sequences were obtained using the Illumina MiSeq platform. It was found that: 1) 484 operational taxonomic units (OTUs) were detected, and 327 OTUs (67.56% of the total OTUs) belonged to five main bacterial groups. The best additive amount of OTUs was the value in treatment group Ⅰ. 2) Across treatment groups from control to Ⅳ, both ACE index and Chao index first increased, then decreased and finally increased, with group Ⅰ significantly higher (P<0.05) than the control group. Compared with the control group, Sobs, ACE and Chao indexes of group Ⅳ were not significantly different (P>0.05). The Shannon and Simpson indexes displayed no significant differences between groups (P>0.05). 3) At the phylum level, between the bacterial groups Firmicutes and Bacteroidetes, no significant differences in relative abundance were observed (P>0.05). At the genus level, relative abundance of Clostridium relative displayed a rising trend across the treatment series (P>0.05), with Clostridium relative abundance in group Ⅰ and Ⅲ, compared with the control group, significantly increased (P<0.05). Similarly, compared with the control group, relative abundance of Coprococcus 1 was significantly increased (P<0.05) in group Ⅱ, while Anaerotruncus relative abundance was significantly increased (P<0.05) in treatment groups Ⅱ and Ⅳ, and relative abundance of NC2004 was significantly increased in treatment group Ⅲ (P<0.05). UCG-014, Erysipelotrichaceae and Ruminococcaceae also displayed significant differences in relative abundance between treatment groups. It is concluded that dietary supplementation with alfalfa meal and alfalfa flavonoids can change the taxonomic composition and community structure of colonic bacteria of weaned piglets, further affecting digestion and metabolism of the nutrients.

Effect of different proportions of oat hay and alfalfa on in vitro fermentation in simulated donkey ceca

LIANG Ting-yu, LANG Xia, WU Jian-ping, WANG Cai-lian, LIU Li-shan, ZHANG Rui, WEI Sheng

2019, 28(6):  185-195.  DOI: 10.11686/cyxb2018698

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This study investigated the effects of mixing oat hay and alfalfa in different proportions, on in vitro fermentation rate when incubated with donkey cecum fluid, so as to provide a theoretical basis to determine the optimal use of roughage in donkey breeding. Oat hay and alfalfa were mixed in ratios of 80:20, 60:40, 40:60, 20:80, denoted as treatment groups Ⅰ, Ⅱ, Ⅲ, and Ⅳ respectively. Each mixture was cultured for 2, 4, 8, 12 and 24 hours using continuous fermentation in an artificial rumen, and in vitro gas production measured. There were 3 replicates at each time point. After termination of fermentation, fermentation parameters and nutrient degradation rate of forage were determined. The results showed: 1) With increased alfalfa proportion in the ration, the dry matter (DM) and acid detergent fiber (ADF) degradation rates increased gradually, and were significantly higher for group Ⅳ than for group Ⅰ (P<0.05); there was no significant difference in the degradation of neutral detergent fiber (NDF) (P>0.05). 2) With increase in alfalfa content, the pH increased gradually, and group Ⅳ was significantly higher than group Ⅰ (P<0.05); The gas production (GP) of group Ⅱ was significantly higher than that of the other three groups at each time point (P<0.05). 3) The concentration of NH₃-N in groups Ⅲ and Ⅳ was significantly higher than for groups Ⅰ and Ⅱ from 12 hours (P<0.05). At 24 h, the concentration of microbial protein in group Ⅱ was significantly higher than in group Ⅲ (P<0.05), and there was no significant difference between groups Ⅰ, Ⅱ and Ⅲ (P>0.05). 4) The combination of oat hay and alfalfa had significant effects on volatile fatty acids (VFA), the concentration of propionic acid in groups Ⅰ and Ⅳ was significantly higher than that in groups Ⅱ and Ⅲ at 24 h (P<0.05), while the total VFA content in groups Ⅰ and Ⅱ was significantly higher than that in group Ⅲ and Ⅳ (P<0.05). 5) After 24 h of fermentation, a positive interaction effect was observed in groups Ⅰ, Ⅱ and Ⅳ, with the interaction being largest in group Ⅳ. Conversely, a negative interaction effect was observed in group Ⅲ. We concluded that the optimal proportion of oat hay and alfalfa was 20:80 (group Ⅳ), as the degradation rate of DM, NDF and ADF was improved, and a higher interaction effect occurred.

Effects of different nutrition levels on growth performance, carcass characteristics and meat quality of Wuzhumuqin lamb

DU Shuai, YOU Si-han, BAO Jian, Gegentu, JIA Yu-shan

2019, 28(6):  196-203.  DOI: 10.11686/cyxb2018317

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The objective of this study was to investigate the growth performance, carcass characteristics, meat quality and fatty acid composition of Mongolian lamb fed pellet and complete pellet. Twenty healthy Mongolian lambs of the same age (six months) and similar body weight (28.83±0.19) kg were randomly divided into two groups, and a control group of ten sheep were fed solely grass pellet, while a second trial group were fed grass pellet with concentrate. It was found that feeding grass pellet with concentrate significantly increased the average daily gain from 56.33 g·d^-1 (control) to 60.00 g·d^-1 (trial group). A very large number of parameters determined showed no difference between control and trial groups, including: body weight before slaughter, carcass weight, dressing percentage, crude protein (CP), ether extract (EE), organic matter (OM), dry matter (DM), calcium (Ca), phosphorus (P), pH₁, pH₂₄, marbling score, Lightness (L^*), cooking yield, shear force, C6:0, C8:0, C10:0, C11:0, C17:1n7, C18:2n6c, C20:1, C20:2, C20:3n3, C20:5n3, C22:2n6, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), ∑n-6, ∑n-3, Val, Met, Leu, Phe, Lys, EAA (essential amino acid), Asp, Ser, Gly, Ala, Cys, His, Pro, NEAA (nonessential amino acid), EAA/NEAA of control group and trial group (P>0.05). Parameters higher (P<0.05) in the trial group than in the control group were: net meat mass, net meat percentage, loin muscle area, GR (carcass fat content) value, redness (a^*), yellowness (b^*), cholesterol, water loss rate, C13:0, C14:0, C17:0, C18:3n6, C18:3n3, C20:0, Ile, Tyr, Arg. Conversely, parameters higher (P<0.05) in the control group than in the trial group were: C4:0, C12:0, C14:1n5, C15:0, C15:1n5, C16:0, C16:1n7, C18:0, C18:1n9c, n-6/n-3, Thr and Glu. These results indicate that feeding Wuzhumuqin lamb is more beneficial to growth performance and meat quality than feeding grass pellet with concentrate.

A brief review of the origin and dissemination of Alfalfa

SUN Qi-zhong, LIU Qian, LI Feng, TAO Ya, XU Li-jun

2019, 28(6):  204-212.  DOI: 10.11686/cyxb2018324

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The origin and spread of alfalfa has not only a taxonomic dimension, but also a historical one. Awareness of alfalfa’s origins is important background knowledge in the field of forage science and history, and also an important research topic in agronomy and agricultural history. Alfalfa, has been cultivated since ancient times, and its origin and transmission has attracted much attention. Iran has been widely recognized as a geographical center for alfalfa. There are two different origins of alfalfa: one is the modern European alfalfa from the Outer Caucasus mountain area; the other is the Central Asia. This latter area is steeped in history, and like the Caucusus is very hot and dry in summer, but differs in being warm in winter. Carbonized alfalfa seeds found in archaeological sites in Iran prove that alfalfa is an ancient crop. About 8000 years ago, humans began to use alfalfa. Records of alfalfa from Turkey date back to 1300 BC, and alfalfa is mentioned in the teaching books of Babylonians in 700 BC. Like some other crops, alfalfa is also transmitted through maritime trade and military invasion. Alfalfa was the main feed of the ancient war horse. Around 490 BC, when the Persians invaded Greece, the seeds of alfalfa were also brought to Greece. The date of alfalfa introduction to Italy is uncertain, probably in 200 BC. At the same time that alfalfa was introduced into Italy, Zhang Qian, the messenger sent to the western world by Emperor Wu of the Han dynasty in 126 BC, brought alfalfa seeds to China. By 1550, alfalfa use had expanded from Spain to France; by 1565 to Belgium and Holland; by1650 to Britain, about 1750 to Germany and Austria, 1770 to Sweden, and in the eighteenth Century to Russia. Then in 1800 alfalfa was taken to New Zealand from Europe, and in 1806 to Australia. Alfalfa was introduced to Peru in 1535. By the eighteenth Century, alfalfa had been introduced into Argentina, and from Peru to Chile. Alfalfa was introduced into the United States from Mexico in 1736.