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2020 Vol.37(5)

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2020, (5): -.
[Abstract](3821) [FullText HTML] (912) [PDF 348KB](71)
Conversion efficiency of porkers’ secondary products: A historical perspective
XU Gang, GUN Shuangbao, REN Jizhou
2020, 37(5): 827-832. doi: 10.11829/j.issn.1001-0629.2020-0046
[Abstract](3684) [FullText HTML] (1308) [PDF 11985KB](29)
In this paper, the developmental process of feeding biological efficiency in pork production, from wild boar raising to domestic swine rearing, was analyzed on the basis of the feed conversion rate. The history of domesticating wild boars into reared swine is as long as the history of human settlement, and the distribution of domestication areas was wide. From the primitive clan society to the small farming agricultural society to the modern industrialized society, the biological efficiency of feed conversion in porker raising, from primary production to secondary production, was improved 20 times. The feed conversion rate of porker raising was 1∶8~1∶10 in the primitive clan society, and 1∶4~1∶6 in the small farming agricultural society. Currently, the feed conversion rate of porker raising is 1∶3.5 in the primarily modernized society. In 2017, the share of primarily modern porker raising and that of scattered porker raising by individual households was 50% for each. If scattered porker raising can be transformed into primarily modern porker raising, about 40.05 million tons of Food Equivalent Units (FEU) can be saved,which is about annual production of the Shaanxi, Gansu and Shanxi Provinces. Although a small amount of human food is used as swine feed, there are significant differences in the ecological niches of human food and swine feed. If they are both treated separately in national production planning and statistical data, different projects will be able to provide evidence for rebuilding the Chinese agro-ecosystem, and agricultural productively can be significantly promoted in alignment with the principles of ecosystem diversity.
Soil organic carbon and its influencing factors on the different plant communities in the middle reaches of the Heihe River wetland
WANG Yuanbo, ZHAO Ruifeng, ZHANG Lihua, ZHANG Xiaoya
2020, 37(5): 833-844. doi: 10.11829/j.issn.1001-0629.2019-0557
[Abstract](6659) [FullText HTML] (1077) [PDF 1170KB](38)
Wetlands are one of the important components of the global carbon cycle. They have unique ecological and environmental effects and functions and play an important role in regulating global climate change. In this paper, a wetland in the middle reaches of Heihe River was taken as the research object. Based on field sampling data, plant community sequencing, and structural equation modeling, the soil organic carbon differences and influencing factors of the different plant communities were analyzed. The results showed that there were significant differences in soil organic carbon among the different plant communities in wetland (P < 0.05), and the soil organic carbon content ranged from 3.56~4.30 g·kg –1, showing obvious surface aggregation. Soil organic carbon is mainly affected by bulk density, pH, soil total nitrogen, soil moisture, soil available nitrogen, soil salinity, dominant species coverage, total abundance, total coverage, and forb coverage. The contribution of soil physical and chemical properties to soil organic carbon change was 0.55, while the contribution of plant community characteristics to soil organic carbon change was 0.22, indicating that the main reason for soil organic carbon change in plant communities in the middle reaches of Heihe River was the difference in soil physical and chemical properties. The influence of soil physical and chemical properties of soil organic carbon took two different paths: 1) the soil directly affects the physical and chemical properties of soil organic carbon and 2) pH and salt influence the total soil organic carbon abundance. These results show that soil organic carbon change is not the result of a simple direct effect as various influencing factors have indirect effects. The results of this study have certain reference value for soil organic carbon sequestration in wetlands of arid areas.
Effects of vegetation restoration on the species composition and diversity of plant communities in the limestone mountains in northern Anhui Province
LIU Xiaoli, ZHANG Xiaochun, LIU Yishan, ZHANG Weiran, SUN Tao
2020, 37(5): 845-852. doi: 10.11829/j.issn.1001-0629.2019-0475
[Abstract](3994) [FullText HTML] (1078) [PDF 479KB](35)
In order to assess the effect of ecological afforestation patterns on the vegetation structure and botanical composition of a typical rocky mountain area in northern Anhui Province, the vegetation community structure, species diversity, and life-form composition were surveyed and analyzed via ecological survey and mathematical analysis. The results showed that there were 54 species of plants in the present research areas, belonging to 26 families and 54 genera. The artificial mixed forest of Platycladus orientalis and Broussonetia papyrifera possessed (MFPB) 16 families and 26 species, occupying 61.5% and 48.4% of the total families and species. The shrubs Ziziphus jujuba var. spinosa and V. negundo var. cannabifolia (SZV) and the grass-shrubs Arthraxon hispidus and V. negundo var. cannabifolia (GSAV) had 32 and 33 species, respectively, which take up 59.3% and 61.1% in all species. Plant life-form composition varied in the different vegetation communities, phanphytes (Ph) was most dominant component in the artificial mixed forest of MFPB, while the second dominant one was chamaephytes (Ch) in ZV and the grass-shrub of AV. The species diversity analysis indicated that, Shannon-Wiener index and Simpson evenness index represented MFPB > SZV > GSAV, and the species richness was in the order of GFAV > SZV > MFPB. The higher value of Sörense was found between ZV and PB, as well as ZV and AV, and the AV hade the lower value of Sörensen. The distinctive landscape characteristics, anthropogenic disturbance and afforestation have important influence on the plant community assembly, diversity and life-form composition.
Study on the community characteristics and biomass allocation of different vegetation in the Eastern Qilian Mountains
LEI Longju, ZHAO Jinmei, ZHANG Xue, XU Changlin, LIU Yinlin
2020, 37(5): 853-863. doi: 10.11829/j.issn.1001-0629.2019-0415
[Abstract](3121) [FullText HTML] (1004) [PDF 889KB](30)
In order to clarify the community characteristics and biomass distribution of different plant communities, the alpine shrub and grassland communities of the Eastern Qilian Mountains were investigated in the field and analyzed in the laboratory. A sample plot survey method was used to study six different plant communities. The results showed that there were 91 species of grass plants in the study area belonging to 22 families and 55 genera and 6 species of shrub plants belonging to 3 families and 4 genera. There were significant differences in density, coverage, and species number among the different shrub communities (P < 0.05) but no significant differences in density, coverage, or species number among the different grassland communities ( P > 0.05). There was no significant difference in the aboveground biomass of grasses among the different plant communities, and the biomass of grasses of the willow shrub grassland on sunny slopes was lower than that of the Rhododendron shrub grassland on shady slopes. There were significant differences among the different plant communities ( P < 0.05). The aboveground biomass of the willow shrub community on sunny slopes was higher than that of the Rhododendron shrub community on shady slopes. The underground biomass of the willow shrub community on sunny slopes was lower than that of the Rhododendron shrub community on shady slopes. There were significant differences in the aboveground and underground biomass among the different shrub communities ( P < 0.05). In different plant communities, shrub biomass increased with the increase in shrub height, which accorded a linear relationship. It can be seen that different plant communities are constrained by climate, environmental conditions, and species distributions, which results in significant differences in community characteristics and biomass distribution ( P < 0.05). The results provide a theoretical reference for estimating the productivity of alpine shrub grassland communities and the rational exploitation and utilization of vegetation resources in the Eastern Qilian Mountains.
ZjSGR gene editing of Zoysia japonica using the CRISPR/Cas9 system
LI Lijing, ZHANG Na, ZHANG Zhiwei, GAO Ya'nan, ZHANG Jiahang, DUAN Mengqi, XU Lixin
2020, 37(5): 864-871. doi: 10.11829/j.issn.1001-0629.2020-0022
[Abstract](3173) [FullText HTML] (979) [PDF 799KB](27)
Zoysia grass (Zoysia japonica) is a common warm-season turfgrass and forage grass species with many excellent characteristics. However, early leaf de-greening occurs in northern parts of China in late autumn and early winter. This limiting factor restricts the wide usage of Zoysia japonica. ZjSGR, a senescence inducing gene isolated from Zoysia grass, plays a negative role in the Zoysia grass leaf color retention process. In this study, the CRISPR/Cas9 system was used to edit the ZjSGR gene of Zoysia japonica by particle bombardment transformation. One ZjSGR mutant plant was obtained after sequencing verification. The mutant plants which appeared dark green had a higher concentration of chlorophyll under natural conditions (28~30 ℃) compared to wild-type plants (P < 0.05). This study provides plant materials for further functional studies of the ZjSGR gene. The mutant plants are a valuable germplasm for the stay-green type Zoysia grass breeding program.
Effects of herbicides on seed germination and seedling physiological characteristics of Festuca arundinacea and Dichondra repens
HUANG Yumei, DENG Chuxuan, LI Jianping, YE Tongfu, WEI Haibing, SANG Tian, XIE Wenfeng
2020, 37(5): 872-881. doi: 10.11829/j.issn.1001-0629.2019-0507
[Abstract](3262) [FullText HTML] (927) [PDF 939KB](18)
The effects of glyphosate and 2, 4-D butylate on the seed germination and seedling growth of Festuca arundinacea and Dichondra repens were researched using seed soaking and leaf spraying, respectively. Generally, the germination rates of Festuca arundinacea and Dichondra repens were inhibited by glyphosate, and the effects intensified with the increase in concentration. Both the shoot height and root length of the two kinds of turfgrass seedlings were also significantly reduced by glyphosate (P < 0.05). The responses of the physiological indices of two kinds of turfgrass to 2, 4-D butylate were basically the same. With the increasing extent and duration of 2, 4-D butylate stress, the malondialdehyde (MDA) and proline content of seedling leaves increased, whereas both the activity of superoxide dismutase (SOD) and chlorophyll content declined. This study highlights that glyphosate highly inhibited the germination rate and seedling growth of two kinds of turfgrass, and 2, 4-D butylate affected the physiological characteristics of D. repens seedlings negatively as well as those of F. arundinacea.
Effects of slope nature on the root morphology and pull-out force of Deutzia scabra and Lespedeza bicolor
SUN Zhenzhou, LI Yiqiang, SONG Guilong, CAO Yuhai, HU Xingbo, DAI Liang, WU Huaqiang
2020, 37(5): 882-888. doi: 10.11829/j.issn.1001-0629.2019-0520
[Abstract](2664) [FullText HTML] (865) [PDF 815KB](16)
In this study, Deutzia scabra and Lespedeza bicolor, the dominant local shrubs in the Songshan Area, were selected as the research objects. The root morphology and pull-out force of the two plants in rocky and soil slopes were studied by root digging, in situ pull-out force, and Win-RHIZO root scanning methods in order to provide theoretical assistance for the study of suitable growth strategies for plant roots as well as slope protection under different natural slope conditions. The results showed that: 1) In rocky slopes, the root length density, root weight density, and specific root length of D. scabra were significantly larger than those of soil slopes (P < 0.05). In rocky slopes, the root length density and specific root length of L. bicolor were significantly less than those of the soil slopes (P < 0.05), while the root weight density was not significantly difference between the two environments ( P > 0.05). 2) A significant difference in the number of basal roots of D. scabra under two slope conditions was present (P < 0.05), and there was no basal root in soil slope. In rocky slopes, the diameter of the basal roots of L. bicolor was significantly larger than that of soil slopes (P < 0.05), while the number of basal roots were no significant difference ( P > 0.05).3) Compared with what was present aboveground, slope nature had a greater influence on root biomass. In rocky slopes, the root biomass and root-shoot ratio of two species of plants were significantly greater than those of plants from the soil slopes ( P < 0.05). 4) The slope nature had an obvious effect on the maximum pull-out force of the plant roots, and D. scabra and L. bicolor showed a strong ability for slope protection on rocky and soil slopes. In short, slope nature has obvious effects on root morphological and mechanical properties of D. scabra and L. bicolor. The root system adapts to the complex underground environment by changing its spatial modeling and distribution strategies so as to maximize its growth efficiency and slope protection benefits.
Effects of improving soil fertility by planting different leguminous green manure plants under different mixed cropping patterns
ZHU Yaqiong, JIAN Dawei, ZHENG Wei, WANG Pu, LI Songsong, HAO Shuai, Naerkezi, LIU Yuehan, Ailifeire
2020, 37(5): 889-900. doi: 10.11829/j.issn.1001-0629.2019-0524
[Abstract](2684) [FullText HTML] (919) [PDF 809KB](27)
Field experiments were conducted in Zhaosu, Xinjiang, from 2017 to 2018 to illuminate the influence of green legume manure plants peanuts, chickpeas, and white sweet clover on soil nutrient concentrations and the aboveground biomass of selected intercropped/rotated crops corn, oilseed rape, barley, and oat. The improvement of soil nutrients was compared under different planting patterns by measuring changes in soil organic matter, nitrogen, phosphorus, and potassium concentration, aboveground biomass, and land equivalent ratios. The results showed that: (1) Compared with a crop monoculture, the green legume manure plants intercropped with corn, mixed oilseed rape, barley, and oat rotations had improved soil organic matter, total nitrogen, and alkali hydrolyzed nitrogen of the soil surface. However, the planting patterns had little effect on total potassium concentration in the soil surface. Furthermore, the sweet clover + barley and oats rotations improved the total phosphorus and available phosphorus concentration of the soil surface. The spatial structure of intercropped and mixed patterns also affected improvements in soil nutrient concentrations. (2) Compared with the soil nutrient concentration before the field experiment, soil organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzed nitrogen, and available phosphorus increased by 40.43%, 50.00%, 10.00%, 27.93%, 76.75%, and 45.13%, respectively, under the white sweet clover + barley rotation. (3) The aboveground biomass of maize, oilseed rape, and white sweet clover for mixed cropping treatments increased by 23.16%, 16.67%, and 27.30%, respectively, when compared with a monoculture. There was a quadratic polynomial function between the increment of aboveground biomass and soil nutrient concentration. Therefore, green legume manures + grass rotations and mulches in the soil, and peanut and corn intercropping improved soil quality by increasing the soil nutrient concentrations of farmlands in Wuerhe area. The planting patterns also produced a crop yield that can provide economic returns. The improvement of soil quality will help to improve the sustainable development of agriculture in this area.
Diversity of seed endophytic bacterial and fungal communities of eight alpine meadow grassland species
GUO Jianxiu, WANG Zhaofeng, Saman BOWATTE, HOU Fujiang
2020, 37(5): 901-915. doi: 10.11829/j.issn.1001-0629.2019-0306
[Abstract](3566) [FullText HTML] (1131) [PDF 808KB](34)
Plant seeds are involved in the transmission of microorganisms from one plant generation to the next, acting as initial inoculums for the plant microbiomes of a wide range of species. It has been well established that seed-borne microbes can establish themselves in various plant parts and provide a range of benefits to their host plants. Previous studies have characterized the seed microbiomes of several agricultural crops, but the seed microbiomes of grassland species are still poorly defined. The aim of this study was to characterize the seed microbiomes of eight grassland species that are dominant among the alpine meadow grasslands of the Qinghai Tibetan Plateau (QTP) using Illumina MiSeq DNA sequencing. The results showed a diverse consortia of bacteria and fungi (115 bacterial genera and 135 fungal genera) that thrive inside the seeds of eight grassland species. The bacterial and fungal communities inside the seeds were significantly different among the eight grassland species. The dominant seed bacterial and fungal phyla of the eight grassland species were Proteobacteria and Ascomycota, respectively. The bacterial genera Pseudomonas, Pantoea, and Ochrobactrum, and the fungal genera Botrytis, Bullera, and Didymella were found in the seeds of all eight grassland species. There were also bacterial and fungal genera unique to each of the seeds of the eight grassland species. This study showed that plant identity is an important factor shaping the seed microbiome. Some of the microbes identified in this study have been previously identified as being beneficial to their host plants, hence the results of this study can be used for future studies on seed microbiome manipulations to ensure healthy and productive grasslands.
Mitigating effect of exogenous 2, 4-epibrassinolide on the inhibition of oat seed germination under salt stress
KOU Jiangtao
2020, 37(5): 916-925. doi: 10.11829/j.issn.1001-0629.2019-0469
[Abstract](2625) [FullText HTML] (849) [PDF 929KB](21)
Oat seeds of Jiayan 2 and Qingyin 2 (Avena sativa) were used as materials to study the osmosis of exogenous 2, 4-epibrassinolide (EBR) in the germination, seedling growth, and germination of oat seeds under salt stress by adding exogenous 2, 4-Epibrassinolide (EBR) with 100 mmol·L–1 NaCl. The aim of this study was to clarify the physiological mechanism of exogenous BRs regulating oat seed germination under salt stress. The results showed that: 1) with 100 mmol·L–1 NaCl stress, the osmotic adjustment ability and antioxidant enzyme (superoxide dismutase, SOD; ascorbate peroxidase, APX; guaiacol peroxidase, GPX) activity of Jiayan 2 and Qingyin 2 oats during seed germination significantly decreased, and the level of reactive oxygen species (·O2, ·OH, H2O2) and MDA content significantly increased, while seed germination and seedling growth were significantly inhibited. 2) Adding 0.01 μmol·L–1 EBR could significantly alleviate the inhibiting effect of 100 mmol·L–1 NaCl stress on oat seed germination. Compared with NaCl stress in the NaCl + EBR treatment, the activity of proteolytic enzymes significantly decreased, the content of soluble protein, soluble sugar, free proline significantly increased, antioxidant enzymes (SOD, APX, GPX, and CAT) significantly increased, and reactive oxygen species (·O2, ·OH, H2O2) significantly decreased. The germination potential, germination rate, germination index, and vigor index of the seedlings significantly increased, while the seedling height, root length, dry weight, and root activity of the seedlings significantly increased. The results showed that exogenous BRs could improve osmotic regulation and antioxidant system activity during the germination of oat seeds under salt stress, inhibit the accumulation of reactive oxygen species and membrane lipid peroxidation products, promote the germination of oat seeds and the growth of seedlings, and improve the salt tolerance of oat seeds during germination.
Nitrogen dynamic of different organs of the energy plant Triarrhena sacchariflora during autumn
ZHAO Chunqiao, ZHU Yi, LI Xiaona, HOU Xincun, YUE Yuesen, FAN Xifeng
2020, 37(5): 926-932. doi: 10.11829/j.issn.1001-0629.2019-0358
[Abstract](2686) [FullText HTML] (914) [PDF 748KB](27)
The objective of this study was to determine whether nitrogen re-translocation was present in the above-ground organs of Triarrhena sacchariflora during autumn. A successive sampling of the energy plant T. sacchariflora was conducted during autumn, and the nitrogen contents in different organs were determined. The results showed that (1) the nitrogen contents in the panicle and stem were the highest and lowest, respectively, among all organs; (2) the nitrogen contents in the panicle, leaf, and stem exhibited gradual decreases, while gradual increases were found in the root and rhizome over time. And the nitrogen contents of the panicle, leaf, and stem samples required at the last time were significantly (P < 0.05) lower by 69.97%, 33.62%, and 32.00%, respectively, when compared with the initial values. The nitrogen contents of the root and rhizome samples required at the last time were significantly ( P < 0.05) higher by 63.86% and 19.90%, respectively, when compared with the initial values; (3) The nitrogen re-translocation of the panicle and stem began after seed formation and lasted longer than that in leaf, while the nitrogen re-translocation of the leaf began later and finished before the first frost. In conclusion, there was obvious nitrogen re-translocation in the above-ground organs of the energy plant T. sacchariflora.
Nutritional value and silage fermentation quality of forage cole in different growth periods
ZHAO Na, YANG Xuehai, WEI Jintao, GUO Wanzheng, CHEN Fang, ZHOU Guangsheng, FU Tingdong
2020, 37(5): 933-941. doi: 10.11829/j.issn.1001-0629.2019-0449
[Abstract](3731) [FullText HTML] (1071) [PDF 464KB](39)
In this paper, we studied the nutritional value, silage nutritional quality, and fermentation quality changes of rapeseed in the lace, initial, and final stages to provide a reference for the utilization of forage rape. The results showed that: 1) with the change in growth period, the GE, EE, CP, thioside content, and RFV of forage rapeseed decreased first and then increased. The concentration of soluble carbohydrates in lace rapeseed were significantly higher than that of the initial stage and final stages, while the content of NDF and ADF were significantly lower than that of the initial and final stages (P < 0.01). The ether extract content in final-stage plants reached 16.02%, which was significantly higher than that of lace-stage and initial-stage plants ( P < 0.01). 2). The pH, acetic acid, butyric acid, ammonia nitrogen/total nitrogen, and V-Scores of rapeseed in the different growth stages were significantly different ( P < 0.05). The pH, lactic acid content, butyric acid content, and V-Scores of rapeseed at different silage times were also significantly different ( P < 0.05). The content of lactic acid and acetic acid in rapeseed during the lace and initial stages increased rapidly, reached maximum values at 60 days, and the content of each treatment group was significantly different ( P < 0.05). The sensory quality and V-Score evaluation of final-stage rapeseed in silage were relatively low. In summary, forage rapeseed at the lace and initial stages has high nutritional value and is suitable for silage, and the silage time is preferably 30 to 45 days.
Effects of nitrogen forms and proportions of nitrogen forms on the growth and physiological characteristics of Elymus sibiricus
WU Zhaolin, QI Juan, LIU Wenhui, JIN Xin, YANG Hang, SU Jinglong, LI Ming
2020, 37(5): 942-951. doi: 10.11829/j.issn.1001-0629.2019-0491
[Abstract](2981) [FullText HTML] (936) [PDF 994KB](21)
To clarify the effects of different nitrogen forms and different ratios of nitrate nitrogen (NO3-N) and ammonia nitrogen (NH4+-N) on the growth and physiological characteristics of Elymus sibiricus, the seeds of wild E. sibiricus were collected from an alpine meadow and used in an experiment. Different ratios of nitrate nitrogen (NO3-N) and ammonia nitrogen (NH4+-N) (0∶10, 3∶7, 5∶5, 7∶3 and 10∶0) were tested using the nutrient solution sand culture method. The results showed that the mixed nitrogen forms promoted the growth of E. sibiricus more than did single nitrogen forms. Plant height, nitrate reductase activity, and the soluble protein content of leaves had the highest values when the ratio of NO3N and NH4+-N was 7∶3, while nitrate reductase activity increased by 48.54% and 74.71% when compared with either effects of nitrate or ammonium, respectively, and the content of soluble protein content increased by 10.16% and 7.30% when compared with effects of nitrate or ammonium alone, respectively. The root vigor was the highest at the ratio of NO3-N and NH4+-N of 5∶5, which increased by 31.05% and 8.08% when compared with effects of nitrate or ammonium nitrogen alone, respectively. In addition, when the ratio of NO3-N and NH4+-N was 3∶7, the root length and total nitrogen content improved significantly and increased to 43.90% and 29.76% when compared with effects of nitrate and ammonium nitrogen alone, respectively. Through a comprehensive analysis using the membership function method, it was found that the ratio of 7∶3 NO3-N∶NH4+-N had the most obvious effects on the growth and physiological characteristics of E. sibiricus.
Influence of high planting density herbal cultivating on yield and quality of whole-plant mulberry (Morus alba)
WANG Honglin, ZUO Yanchun, ZHOU Xiaokang, YAN Xu, KOU Jing, PU Jun, ZHANG Haoren, DU Zhouhe
2020, 37(5): 952-962. doi: 10.11829/j.issn.1001-0629.2019-0445
[Abstract](4341) [FullText HTML] (1001) [PDF 543KB](33)
In order to select the optimum planting density of forage mulberry (Morus alba), a planting density experiment in a randomized complete block design was carried out over three years in Northeast Sichuan, South China, using a forage mulberry cultivar ('teyou No. 2') using three planting densities (75 000, 105 000, and 135 000 plant·ha–1). The above-ground biomass productivity, agronomic characteristics, and feeding value of the whole-plant forage mulberry were evaluated. Results showed that the biomass yield of forage mulberry, including stems and leaves, increased with planting year. Planting density had a significant effect (P < 0.05) on the biomass yield of forage mulberry. The highest yield was obtained under 105 000 plants·ha –1 in the same year. The above-ground biomass increased with increasing leaf content, and the stem-leaf ratio remained constant regardless of initial planting density. Plant height and total branch number increased at first, and then decreased slightly with increasing density. The ranges of plant height and total branch number across the three densities were 75.33~77.00 cm and 11.67~12.33, respectively. The main stem diameter and leaf number per stem decreased with increasing density, and the ranges of these two traits across the three densities were 0.64~0.75 cm and 11.67~12.67, respectively. A significant effect of plant density on feeding value was observed. The crude protein (CP) and ether extract (EE) content of the whole plant increased at first, then decreased with increasing density. The CP and EE contents, which were both highest at 105 000 plant·ha–1, measured in at 16.60% and 3.67% at this density, respectively. The NDF (neutral detergent fiber) and ADF (acid detergent fiber) contents gradually increased with increasing density, with minimums of 42.84% and 30.18% at 75 000 plant·ha–1, respectively. The crude ash content gradually increased with increasing density, and peaked at 8.69% at 135 000 plants·ha–1. The relative feeding value of the whole forage mulberry plant under the three densities ranged from 128.19 to 141.93, demonstrating that the forage mulberry is an excellent food source with a good feeding value at high planting densities. In summary, the optimum cultivation density of forage mulberry for whole-plant harvesting is 105 000 plants·ha–1 in Northeastern Sichuan.
Research progress on β-ODAP and sulfur metabolism of Lathyrus sativus
SONG Yaoyao, ZENG Peng, JIANG Jinglong, JIAO Chengjin, XU Quanle
2020, 37(5): 963-974. doi: 10.11829/j.issn.1001-0629.2019-0336
[Abstract](2929) [FullText HTML] (1024) [PDF 726KB](26)
Lathyrus sativus is a very important food crop in arid, semi-arid, and poor areas. However, the excellent agronomic traits and dietary advantages of L. sativus were disregarded due to the overemphasis on its endogenous toxin, β-ODAP. With changes in global climate, this climate-resilient crop deserves more attention. Here, the current knowledge on the properties of L. sativus as a traditional toxic crop, the role of sulfur metabolism in L. sativus, and its contribution to β-ODAP biosynthesis and drought resistance are reviewed. Moreover, strategies for the improvement of sulfur nutrition in L. sativus are evaluated.
Effects of dietary crude protein level on rumen microbial composition and the fermentation parameters of finishing Hu lambs
NIU Xiaolin, GUO Tao, ZHOU Wenjing, GUO Long, LI Fei, LI Fadi
2020, 37(5): 975-983. doi: 10.11829/j.issn.1001-0629.2019-0439
[Abstract](2268) [FullText HTML] (663) [PDF 562KB](28)
The objective of this study was to evaluate the effects of dietary CP levels on the rumen and its contents, pH, and microbial and volatile fatty acid (VFA) concentrations in finishing Hu lambs. A total of 54 three month old male Hu lambs [(32.25 ± 2.50 kg)] were randomly divided into three groups based on their weights. The dietary CP levels were 11.5%, 14%, and 16.5%, respectively. Each group contained 18 replicates, and a replicate consisted of one lamb. The pre-test period was 7 days, and the formal experiment lasted 63 days. A total of 10 lambs were selected for slaughter in each group at the end of the test period. Then, the slaughter performance was measured and the rumen contents were collected so that the rumen microbial DNA could be extracted. The results showed that 1) the different CP treatments had no significant effect on live weight before slaughter, carcass weight, slaughter rate, the total weight of the rumen, rumen tissue weight, and tail fat weight; 2) the ammonia nitrogen in the rumen fluid of the 11.5% CP group was significantly lower than in the rumen fluid of the 14.0% CP and 16.5% CP groups (P < 0.001), but there was no significant difference between the 14.0% CP group and the 16.5% CP group ( P > 0.05). Rumen pH increased as dietary protein levels rose ( P < 0.1). 3) The TVFA concentration, and the acetate, propionate, isobutyrate, butyrate, and valerate ratios were not affected by the CP level ( P > 0.05). However, the isovalerate ratio tended to increase ( P = 0.098) as the CP level in the diet rose. 4) Butyrivibrio fibrisolvens levels in the rumens from the different treatment groups were higher than the other bacteria, but there were no significant differences among the treatment groups (P > 0.05). The Ruminococcus albus, Fibrobacter succinogenes, and Prevotella brevis contents were not affected by CP level (P > 0.05), whereas the Ruminococcus flavefaciens levels were significantly lower in the 11.5% CP group than in the 14.0% CP group (P < 0.05). The 16.5% CP group was not significantly different from 11.5% CP and 14.0% CP groups. These results indicated that the different CP levels did not affect the slaughter performance of the Hu lambs, but could affect the pH and ammonia nitrogen content of the rumen fluid. Furthermore, the isovalerate proportion increased as the CP levels rose, and the Ruminococcus flavefaciens levels were highest in the 14.0% CP group.
Effect of oligosaccharide addition on rumen bacterial flora of lactating calves
YE Wenxing, ZHANG Jie, CHEN Lin, JIN Yadong, CAO Zhijun, XU Xiaofeng
2020, 37(5): 984-992. doi: 10.11829/j.issn.1001-0629.2019-0502
[Abstract](2643) [FullText HTML] (914) [PDF 528KB](24)
The effects of different methods mannose oligosaccharide (MOS) addition on the construction of rumen bacteria in calves were studied based on 16S rDNA sequencing. Twenty healthy male Holstein calves with similar weights and of the same age were selected and randomly divided into four groups. The control group (CR) was fed a basal diet of milk with no MOS added. In the ORa group, 5 g MOS was added to the milk rather than the diet. In the ORb group, 5 g MOS was added to the diet rather than the milk. In ORc group, 2.5 g MOS was added to both the milk and diet, respectively. The results showed that the different methods of MOS addition affected the total amount of rumen bacteria, but no significant influence on the diversity of rumen bacteria in calves was found. At the phylum level, compared with that of the control group, the addition of MOS in the ORb group significantly reduced the abundance of Firmicutes and Actinomycetes (P < 0.05) and significantly increased the abundance of Proteobacteria ( P < 0.01). The dominant bacteria in the ORb group increased to 3 species (Bacteroidetes, Firmicutes, and Proteobacteria). At the genus level, the different methods of MOS addition effected the structure of rumen bacteria of the calves to some extent, including Dialister and Desulfovibrio. While the variables had fewer effects on the rumen bacteria of calves in the ORa and ORc groups compared to that of the ORb group. Moreover, the functional rumen bacteria of the calves in the ORb group were all significantly affected, including prevoort-7, amino acid cocci, eubacterium, and vibrio succinate. In this experiment, the different ways of adding MOS had no significant impact on the diversity of rumen bacteria of suckling calves. However, the method of MOS addition in the starter had some effects on the structure of the flora, among which the abundance of Succinivibrionaceae_UCG-001, which played a role in both rumen protein degradation and starch degradation, significantly increased. The abundance of Selenomonas using lactic acid significantly increased, and the abundance of Eubacterium_coprostanoligenes_group using lactose significantly reduced, while the abundance of Dialister degrading hemicellulose significantly reduced.
Optimization of leaf protein extraction process and key parameters of Medicago polymorpha in the agricultural areas of Lower Yangtze River
XU Zhuo, CHEN Zhen, WU Guicheng, HANG Jie, GUAN Yongxiang, SUN Zhengguo
2020, 37(5): 993-1001. doi: 10.11829/j.issn.1001-0629.2019-0451
[Abstract](2438) [FullText HTML] (907) [PDF 927KB](16)
The objective of this study was to improve and optimize the process of extracting leaf proteins from Medicago polymorpha and to improve the extraction rate of leaf proteins and extract purity. M. polymorpha was selected for this study and is widely cultivated in the agricultural areas of the lower reaches of the Yangtze River as a raw material. A single factor test for leaf protein extraction was carried out by setting a reasonable and scientific material-liquid ratio, extraction temperature, heating time, pH, and extractant (acid) type. The results showed that the optimal parameters of each single factor test were: 1∶3 material-liquid ratio; 70 °C extraction temperature; 15 min heating time; pH 4.0; and a hydrochloric acid extractant. Based on the clean and safe production angle, citric acid with the same high extraction rate for the single factor test was selected as the extractant, and the 3 factors and 3 level responses of the surface test of the material-liquid ratio, pH, and extraction temperature were set. It was found that the extraction rate of leaf proteins was affected, and the order of these factors was pH, extraction temperature, and material-liquid ratio. The optimal extraction process was: 1∶3 ratio of material to liquid, pH 4.1, 72 °C extraction temperature, 49.63% leaf protein extraction rate, and a 56.87% extract purity rate. The optimized technical process and related parameter indicators of this experiment can provide certain technical support and related references for the diversified utilization of leguminous plants in agricultural areas and the industrial production of leaf proteins.
Silage of abandoned-growing branches of Lycium barbarum
YANG Qifang, CHEN Kaiqiong, GOU Qi, LYU Yan, LIU Jianli
2020, 37(5): 1002-1009. doi: 10.11829/j.issn.1001-0629.2019-0462
[Abstract](2837) [FullText HTML] (900) [PDF 990KB](27)
Abandoned-growing branches are a waste of Lycium barbarum planting but contain abundant nutrients and medicinal ingredients. Using abandoned-growing branches of L. barbarum as a medicine additive silage is a way to turn waste into treasure. In this paper, molasses, bran, and corn flour were added as silage sugar sources and ‘Ya xin’, ‘Jun an jiao bao’, ‘Yijiayi,’ and ‘Nongfukang’ as commercial silage bacteria. By comparing the sensory evaluation scores, nutrient components, and medicinal components of the different sugar sources and microbial silages, we set out to find silage bacteria and sugar sources suitable for L. barbarum abandoned-growing branches silage. The results showed there were no significant differences in the content of acid detergent fiber, neutral detergent fiber, and ammonia nitrogen in the three kinds of sugar source silage (P > 0.05). The highest content of crude protein (1.18%), crude ash (12.77%), dry matter (30.5%), lactic acid (123.75 μg·g –1), polysaccharide (27.89 mg·g–1), betaine (6.47 mg·g–1), and total flavonoids (1.15 mg·g–1) added to molasses were significantly higher than those of the other two treatments (P < 0.05). There was no difference between the dry matter and ammonia nitrogen content of the four kinds of microbial agents and natural silage ( P > 0.05). However, crude protein (1.96%), acid detergent fiber (75.52%), neutral detergent fiber (73.86%), water-soluble carbohydrate (259.19 mg·g –1), lactic acid (145.82 μg·g–1), and polysaccharide (27.27 mg·g–1) content were the highest in natural silage (P < 0.05). Molasses was deemed to be the best sugar source, and natural silage is the best way of using the abandoned-growing branches of L. barbarum.
Experience in teaching the Grassland Pest Management and Utilization course in English
TIAN Pei, DUAN Tingyu, LI Chunjie, LI Yanzhong, YU Binhua, YUAN Minglong, ZHANG Xingxu, SONG Qiuyan, GU Lijun, XIA Chao, FANG Xiangling, NAN Zhibiao
2020, 37(5): 1010-1016. doi: 10.11829/j.issn.1001-0629.2019-0572
[Abstract](2271) [FullText HTML] (768) [PDF 423KB](62)
Pratacultural science is a leading and characterizing discipline of Lanzhou University as well as double first-class initiative construction discipline. The Grassland Pest Management and Utilization course is one of the most important courses of pratacultural science education. This course of the College of Pastoral Agriculture Science and Technology (CPAST) at Lanzhou University is a National Top Level Course. With the strong the support of College and University, we meet with the basic conditions of English lecturing, which include complete teaching content, a teaching team with a high level of English, and students with good English foundations. Based on these conditions, the Pest Management and Utilization course was imparted in English with modified lecturing methods including improvements in the teaching methodology, a combination of theory and practice, the establishment of English assessment methods, and adjustments according to student feedback. However, there are still some improvements to be made, including the construction of English resources and a reasonable design of teaching content, the creation of and atmosphere for learning and using English, full care of students with different English levels, and optimal Chinese explanations. There are benefits of English lecturing including the simultaneous improvement of the professional and English abilities of the students, which further improves comprehensive professional abilities and confidence. These discussions will provide a reference for the further exploration of the corresponding teaching modes and methods of the Pest Management and Utilization course in English. These comprehensive improvements make students more competitive in international communication setting and in the field of pratacultural science.