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2021 Vol.38(4)

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2021, 38(4): 0-0.
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2021, (4): 1-4.
[Abstract](1522) [FullText HTML] (570) [PDF 337KB](35)
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Variation characteristics of soil water-soluble organic carbon in permafrost regions of the Shule River headwaters
WEI Peijie, LIU Fang, WU Minghui, JIA Yinglan, GAO Yayue, CHEN Shengyun
2021, 38(4): 605-617. doi: 10.11829/j.issn.1001-0629.2020-0401
[Abstract](2087) [FullText HTML] (614) [PDF 1490KB](25)
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Water-soluble organic carbon (WSOC) is the most active component of soil carbon pool, and its production, transport and transformation are of great significance to the evaluation of soil quality, fertility and carbon pool stability. However, little research has been conducted on the changes and influencing factors of soil WSOC in the active layer of permafrost regions of the Qinghai-Tibet Plateau. In this study, the alpine meadow, located at the permafrost regions of Shule River headwaters in the western part of the Qilian Mountains and the northeast margin of the Qinghai-Tibet Plateau was selected as the study area. The variation characteristics of WSOC and WSOC/SOC in the vertical profile and season, as well as their influencing factors were analyzed. We found that: 1) The WSOC seasonal variation was remarkable (P < 0.05) and showed a "V" shape pattern, i.e., high in winter and spring, but low in summer and autumn. 2) WSOC of different soil layers in the same season showed different trends with soil depth (P > 0.05); namely, WSOC decreased with depth in spring, increased with depth in summer, and showed a "V" form in autumn but an inverted "N" form in winter, and the average annual WSOC content generally showed a downward trend with soil depth. 3) The WSOC/SOC ratio showed significant seasonal and vertical changes (P < 0.05), among which WSOC/SOC in different soil layers was largely an "N" type, with high values in winter and summer, low values in spring and autumn, and a seasonal variation range of 0.14% ~ 0.29%. WSOC/SOC in different soil layers in the same season showed different distributions with increasing of soil depth; namely, an "M" type in spring, increasing trend in summer and autumn, and a "V" type in winter. 4) Soil temperature and soil water content were the controlling factors of WSOC seasonal and depth-related (vertical) changes, while pH and soil temperature were the main controlling factors of WSOC/SOC vertical and seasonal changes. Investigation of the seasonal and vertical variation characteristics of WSOC and SOC can provide scientific data for the assessment and prediction of soil carbon pools in the active layer of permafrost in the Qinghai-Tibet Plateau under the influence of global warming scenarios. The variation characteristics of WSOC and WSOC/SOC with seasons and profiles are apparent, and the main control factors vary somewhat.
Effects of simulated warming on the allometric growth patterns of an alpine meadow community on the Qinghai-Tibet Plateau
XU Manhou, YANG Xiaohui, DU Rong, QIN Ruimin, WEN Jing
2021, 38(4): 618-629. doi: 10.11829/j.issn.1001-0629.2020-0694
[Abstract](2106) [FullText HTML] (571) [PDF 726KB](32)
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An alpine meadow on the Qinghai-Tibetan Plateau was chosen as the research object. In the meadow, simulated warming experiments were conducted using infrared radiators, and community growth characteristics were investigated during the plant growing seasons of 2011−2013 and 2016−2018. Four common basic functions (exponential, linear, logarithmic, and power functions) were selected to fit the optimal equations to analyze the allometric relationships of the plant communities under control and warming treatments and explore the effects of the simulated warming on the allometric relationships of the meadow plant communities on the plateau. The results showed that: 1) In the control treatment, the aboveground biomass was significantly and positively correlated with density (P < 0.05), height (P < 0.01), and cover (P < 0.01), whereas in the warming treatment, the aboveground biomass was significantly and positively correlated with frequency (P < 0.01) and cover (P < 0.01), and the root-shoot ratio was significantly negatively correlated with density (P < 0.05) and cover (P < 0.05); 2) The effect of cover on the aboveground biomass increased under the warming treatment (P < 0.01), the effect of frequency on the aboveground biomass changed from insignificant (P > 0.05) to significantly positive (P < 0.01), and density and cover effects on the root-shoot ratio changed from insignificant (P > 0.05) to significantly positive (P < 0.01). The density and cover effects on the root-shoot ratio also changed from insignificant (P > 0.05) to significantly negative (P < 0.05); and 3) Among the four common basic functions, the power function was more consistent with the vegetation growth relationship, indicating that meadow vegetation conformed to the allometry theory. In the control treatment, the aboveground part of the meadow vegetation was in agreeance with the isometric relationship, the belowground part with the allometric relationship, and the overall meadow vegetation with the allometric relationship. In the warming treatment, the aboveground part, belowground part, and overall meadow vegetation all conformed to the allometric relationship. Therefore, the aboveground part of the meadow vegetation changed from an isometric relationship to an allometric relationship, and the belowground part of the meadow vegetation further enhanced the allometric relationship under the warming treatment. The results of this study have theoretical significance for accurately understanding how climate change affects plant growth and community structure in alpine meadows.
Identification and development of EST-SSR markers in Tamarix hispida based on transcriptome sequencing
LI Jiabin, HUANG Lei, ZHANG Ya'nan, JIA Yuanyuan, TIAN Yunyun, ZHANG Lei, DANG Zhenhua
2021, 38(4): 630-639. doi: 10.11829/j.issn.1001-0629.2020-0512
[Abstract](1774) [FullText HTML] (432) [PDF 887KB](10)
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Expressed sequence tag-simple sequence repeats (EST-SSR) may provide a molecular basis for plant adaptation. In this study, we sequenced five individual transcriptomes of Tamarix hispida from different locations, and identified 1 187 polymorphic EST-SSRs. Of the identified SSRs, tri-nucleotide repeats were the most common (54.42%), followed by dinucleotide repeats (37.66%). A total of 500, 176, and 211 EST-SSRs were located in coding region, 3′ untranslated regions (UTRs), and 5′ UTRs in 829 transcripts, respectively. AGC/GCT, AT/AT, and AG/CT were the most abundant repeats in each gene region. Gene ontology functional annotation showed that the identified SSR-containing sequences were enriched in "regulation of transcription" , "transcription factor activity", and "nucleus" terms. KEGG pathway analysis showed that "metabolic pathways" was the most common and abundant term, followed by "plant hormone signal transduction". Using polymerase chain reaction amplification, sequencing, and capillary electrophoresis validation, 13 out of the 15 randomly selected polymorphic SSR markers were developed. The results of this study lay the foundation for the investigation of population genetics and adaptation evolution mechanisms underlying SSR variations in T. hispida.
Research progress on the mechanisms of arbuscular mycorrhizal fungi on drought resistance in plants
YU Zhi, LIANG Kunnan, HUANG Guihua, YANG Guang, ZHOU Zaizhi, LIN Mingping
2021, 38(4): 640-653. doi: 10.11829/j.issn.1001-0629.2020-0495
[Abstract](2157) [FullText HTML] (817) [PDF 731KB](31)
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Plants, as sessile organisms, can adopt various strategies to adapt to external stimuli and adversities. One strategy is the establishment of a symbiotic relationship with arbuscular mycorrhizal fungi (AMF). AMF can form symbiotic relationships with more than 80% of terrestrial plants, promote plant growth and development, and improve plant drought resistance. AMF mechanisms for enhancing drought resistance include promotion of the formation of the soil aggregate structure, improvement of the root architecture, enhancement of water and nutrient uptake, improvement of photosynthesis and water use efficiency, reduction of oxidative damage, strengthening of osmotic regulation, regulation of endogenous hormones, and induction of related gene expression. This study summarized the research progress of AMF on drought resistance in plants both domestically and overseas regarding morphology, physiology, biochemistry, and gene expression and examined the problems of current studies and suggestions for future research.
Bio-ecological characteristics and control strategies of Bradysia impatiens
GOU Yuping, MAO Liang, LIU Changzhong, ZHANG Kexin, LI Chunchun, ZHANG Qiangyan, ZHANG Yanlei
2021, 38(4): 654-663. doi: 10.11829/j.issn.1001-0629.2020-0436
[Abstract](2044) [FullText HTML] (604) [PDF 693KB](12)
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The bio-ecological characteristics and control strategies of Bradysia impatiens Johannsen were summarized in this study. Edible fungus and Chinese chives (Allium tuberosum) are B. impatiens’ most favored host plants for adaptability and food preference. For population growth, the most favorable growth conditions were found to be temperature 25 ℃, photoperiod L ꞉ D = 16 h ꞉ 8 h, and light intensity of 588 lx. Humidity is closely related to the living habits and behavior of insects; however, there are few known studies on this topic for B. impatiens. At present, chemicals remain the main control method for B. impatiens. Potentially better control may be possible, though, by using biological control technologies, such as entomopathogenic nematodes, predatory mites, and Bacillus thuringiensis, and physical control methods, such as high temperature solar film covering and phototaxis. In the present study, we summarize and elaborate the bio-ecological characteristics and control strategies of B. impatiens, with the aim of providing a theoretical basis for further study of B. impatiens.
Effects of salinity, alkalinity, temperature, and their interactions on seed germination and seedling growth of Salvia miltiorrhiza
GUO Meng, HUANG Yong, LI Hemin, ZHANG Hongrui, ZHOU Yan, GAO Zhiming, DING Mengyao
2021, 38(4): 664-672. doi: 10.11829/j.issn.1001-0629.2020-0338
[Abstract](1608) [FullText HTML] (459) [PDF 866KB](16)
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Salviae miltiorrhizae is a traditional Chinese medicinal plant. The effects of four concentrations (6.25, 12.5, 25, and 50 mmol·L−1) of salt solution and four concentrations (3.125, 6.25, 12.5, and 25 mmol·L−1) of alkali solution on seed germination and seedling growth of S. miltiorrhiza seeds were studied under two varying temperatures (18 ℃/28 ℃ and 28 ℃/38 ℃). Salinity, alkalinity, temperature, and their interactions had significant effects on the seed germination and seedling growth of S. miltiorrhiza (P < 0.05). Seed germination and seedling growth were significantly higher under 18 ℃/28 ℃ than 28 ℃/38 ℃ (P < 0.05). Under 18 ℃/28 ℃ and 6.25 mmol·L−1 salt solution, germination of S. miltiorrhiza was stimulated, with a significantly higher germination percentage and germination index than under water control (P < 0.05). Additionally, the relative salt damage rate was significantly lower than under water control (P < 0.05). There was no significant effect of 12.5 mmol·L−1 salt solution and 3.125 mmol·L−1 alkali solution on S. miltiorrhiza seed germination rate, germination index, and relative salt damage rate (P > 0.05). The germination rate and germination index of S. miltiorrhiza were decreased significantly under salt solution at 25 and 50 mmol·L−1and alkali solution at 6.25, 12.5 and 25 mmol·L−1 (P < 0.05), and the salt damage rate increased. Under 28 ℃/38 ℃, salt solution at 6.25 and 12.5 mmol·L−1 and alkali solution at 3.125 and 6.25 mmol·L−1 had no significant influence on the germination rate, germination potential, and relative salt damage rate of S. miltiorrhiza (P > 0.05). Salt solution at 25 and 50 mmol·L−1 as well as alkali solution at 12.5 and 25 mmol·L−1 significantly reduced the germination rate and germination index of S. miltiorrhiza (P < 0.05) and increased the relative salt damage rate. Salt and alkali stress inhibited root growth of S. miltiorrhiza seedlings significantly (P < 0.05). Under the two different temperature conditions, salt solution at 6.25 and 12.5 mmol·L−1 and alkali solution at 3.125 mmol·L−1 had no significant effect on leaf length growth of S. miltiorrhiza seedlings (P > 0.05), whereas 25 and 50 mmol·L−1 salt solution and 6.25, 12.5 and 25 mmol·L−1 alkali solution stress significantly inhibited leaf length growth (P < 0.05). Salt solution at 6.25 mmol·L−1 under 18 ℃/28 ℃ promoted leaf width growth of seedlings, whereas salt solution at 6.25 mmol·L−1 and alkali solution at 3.125 mmol·L−1 under 28 ℃/38 ℃ had no significant effect on leaf width growth (P > 0.05). High salt and alkali stress significantly inhibited leaf width growth (P < 0.05). In conclusion, salinity, alkalinity, temperature, and their interactions had a significant effect on seed germination and seedling growth of S. miltiorrhiza. Salinity and alkalinity had relatively little impact on S. miltiorrhiza seeds under low temperature. Seed germination and seedling growth of S. miltiorrhiza were more sensitive to alkali stress. It is suggested that saline-alkali breeding of S. miltiorrhiza seeds should be carried out on land with low salinity and alkalinity and at a temperature of 18 ℃/28 ℃.
Growth status of Lolium perenne and Medicago sativa and their manganese absorption in manganese residue-soil mixed matrixes
AO Hui, LIU Fang, ZHU Jian, CHEN Zuyong
2021, 38(4): 673-682. doi: 10.11829/j.issn.1001-0629.2020-0640
[Abstract](1902) [FullText HTML] (472) [PDF 746KB](10)
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Using Medicago sativa and Lolium perenne as the experimental materials, the growth status of M. sativa and L. perenne and their absorption characteristics of manganese in electrolytic manganese residue-soil mixed matrixes were examined in this study. The germination rate of M. sativa and L. perenne decreased after mixing variable proportions (7%, 14%, 21%, 28%, and 35%) of electrolytic manganese residue (EMR) in the soil, whereas the biomass first increased and then decreased with an increase in the amount of EMR. The height of the two plants increased to different degrees, especially for L. perenne. With an increase in EMR, the photosynthetic pigment content in L. perenne was increased. In the 14% EMR treatment, the chlorophyll content was the highest, significantly higher than the control by 34.7% (P < 0.05). The chlorophyll and carotenoid content in M. sativa first increased and then decreased with the addition of EMR. In the 14% EMR treatment, the chlorophyll and carotenoid content increased significantly, 59.7% and 28.0% higher than the control, respectively. After adding EMR to the soil, the malonaldehyde (MDA) content and activity of the antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in M. sativa increased significantly, whereas the MDA content and activity of SOD, CAT, and POD in L. perenne did not change, indicating that the tolerance of ryegrass > alfalfa. The manganese content in the aerial parts and roots of M. sativa and L. perenne increased with an increase in EMR. The enrichment coefficient of manganese was L. perenne > M. sativa, and the transfer ability of manganese was M. sativa > L. perenne. Both plants could be used as candidate plants for the ecological restoration of manganese residue; however, the inhibitory effect of manganese residue on M. sativa was greater than that of L. perenne. Therefore, L. perenne was more suitable as a pioneer plant for the ecological restoration of manganese residue.
Evaluation of physiological response and cold resistance of four alfalfa cultivars to low temperature stress
ZHAO Yihang, MENG Lingdong, ZHANG Xiaomeng, WANG Li'na, LIU Haoyue, BI Linlin, LIU Hongliang, YIN Xiujie
2021, 38(4): 683-692. doi: 10.11829/j.issn.1001-0629.2020-0390
[Abstract](1398) [FullText HTML] (506) [PDF 878KB](28)
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Four alfalfa (Medicago sativa) cultivars, ‘Zhaodong’, ‘Longmu 801’, ‘Dongnong No. 1’, and ‘Aohan’, were studied. The cold resistance of the four alfalfa cultivars was comprehensively compared by analyzing physiological biochemical indexes and leaf anatomical structure. The relative electrical conductivity, malondialdehyde content, soluble sugar content, free proline content, peroxidase, and superoxide dismutase activity of the alfalfa cultivars increased compared with the control. Among them, ‘Zhaodong’ had the highest increase in each indicator. Through a comprehensive analysis of the membership function, it was concluded that the cold resistance of the alfalfa cultivars from high to low is as follows: ‘Zhaodong’ > ‘Longmu 801’ > ‘Dongnong No. 1’ > ‘Aohan’. By observing the anatomical structure of the alfalfa cultivars, it was found that the blade thickness, palisade tissue thickness, and sponge tissue thickness of ‘Zhaodong’ and ‘Longmu 801’ with strong cold resistance were less than that of ‘Aohan’, which was less cold resistant, and the cell structure was tighter than that of ‘Aohan’.
Effects of different potassium fertilizers on chlorophyll fluorescence parameters of alfalfa under waterlogging conditions
SONG Shurui, YU Hua, HUANG Ye, ZHANG Weihong
2021, 38(4): 693-702. doi: 10.11829/j.issn.1001-0629.2020-0468
[Abstract](2045) [FullText HTML] (845) [PDF 1457KB](17)
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Waterlogging is animportant abiotic factor that restricts the production of alfalfa in waterlogged areas globally. The addition of elements, for example N, P, and K, can alleviate the damage to plants caused by waterlogging. Thus, the objective of the present study was to investigate the effect of different potassium fertilizers (KCl and KNO3) on chlorophyll content, prompt fluorescence, and delayed fluorescence parameters of alfalfa under waterlogging. The results showed that the addition of KCl and KNO3 can significantly alleviate the damage caused by waterlogging. Both the chlorophyll (Chl) a fluorescence induction transient (OJIP) curve and the delayed fluorescence further indicate that the application of KCl and KNO3 can aleviate damage. The results of this study may provide some suggestions to prevent waterlogging stress in alfalfa and inform further research in the area.
Effects of utilization modes, planting patterns, and nitrogen applications on the yield and quality of perennial forage
XIAO Xiangming, CHANG Shenghua, JIA Qianmin, PENG Zechen, ZHANG Cheng, LIU Yongjie, WU Enping, HOU Fujiang
2021, 38(4): 703-715. doi: 10.11829/j.issn.1001-0629.2020-0359
[Abstract](1842) [FullText HTML] (577) [PDF 600KB](28)
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The objective of this study was to explore the effects of planting patterns and nitrogen applications on forage yield and quality under different utilization modes. Therefore, we applied grazing (G) and mowing (M) treatments on cultivated grasslands in Huan County, Gansu Province. For each utilization mode, there were three planting patterns (W: monoculture of Bromus inermis; H: monoculture of Onobrychis viciifolia; and WH: mixed planting of the two forages) and three nitrogen application levels (N1: 0; N2: 80 kg·ha−1; and N3: 160 kg·ha−1). The results showed that 1) Compared to the M treatment, the G treatment significantly increased the total fresh and hay yields and significantly decreased the crude fat, neutral detergent fiber (NDF), and acid detergent fiber (ADF) content, thus increasing the relative feeding value (RFV). 2) Compared to the W planting pattern, the WH and H planting patterns significantly increased the total fresh and hay yields, with WH significantly higher than H, and significantly increased the crude protein and crude fat content, significantly reducing the NDF content, and significantly increasing the RFV. 3) The total fresh and hay yields increased significantly with the increase in nitrogen application, and the crude protein and crude fat content of the N2 and N3 treatments were significantly higher than those of N1, whereas the NDF and ADF content were significantly lower than those of N1, and RFV was significantly higher than that of N1. Therefore, the planting pattern of mixed grassland of B. inermis and O. viciifolia and nitrogen application of 160 kg·ha−1 are suitable management strategies for the cultivated grazing grassland in East Gansu.
Effects of nitrogen forms on nitrogen accumulation and utilization of alfalfa in different stubbles
LIU Wentao, WANG Yuqiang, SUN Shengnan, ZHAO Yi, SHEN Yu, QIAN Jin, YAN Xuebing
2021, 38(4): 716-725. doi: 10.11829/j.issn.1001-0629.2020-0511
[Abstract](1830) [FullText HTML] (431) [PDF 1367KB](15)
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To study the effects of nitrogen forms on nitrogen accumulation and utilization of alfalfa in different stubbles, this study adopted a completely random design with the following treatments: a control (no nitrogen application), a single application of nitrate nitrogen, a single application of ammonium nitrogen, and a 1 ꞉ 1 mixed fertilization of nitrate nitrogen and ammonium nitrogen. Various application methods of different forms of nitrogen fertilizer on alfalfa production were also examined. The results showed that the soil nitrate nitrogen content of each treatment was significantly higher than that of the control (P < 0.05). With increasing stubbles, the soil nitrate nitrogen content of the mixed nitrogen application was the highest. The soil ammonium nitrogen content did not change significantly under different treatments and stubbles (P > 0.05). The nitrogen accumulation, nitrogen absorption efficiency, and nitrogen utilization efficiency of alfalfa in the mixed nitrogen and single nitrate nitrogen applications were significantly higher than those of the single ammonium nitrogen application treatment during the first growing year (P < 0.05) and reached a peak in the second stubble. Therefore, single applications of nitrate nitrogen and mixed nitrogen are more conducive to increasing the yield of alfalfa and enhancing its absorption, utilization, and accumulation of nitrogen. As the number of stubbles increased, the dependence of alfalfa on nitrogen increased, and nitrate nitrogen or mixed nitrogen must be added as fertilizer to ensure its yield and quality after the second stubble, thereby improving feed quality.
Study of the water absorption depth of fruit trees based on stable isotope technology: Using the different fruit-grass complex systems in Luochuan Loess Tableland as an example
ZHANG Lu, ZHAO Ni, GE Jianzhen, CHENG Jimin, JIN Jingwei
2021, 38(4): 726-737. doi: 10.11829/j.issn.1001-0629.2020-0596
[Abstract](2129) [FullText HTML] (491) [PDF 946KB](13)
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Water resource shortage and low water use efficiency are the limiting factors of sustainable development of the fruit industry in the Luochuan Loess Tableland. Therefore, it is important to accurately measure the water absorption depth of plants and analyze their water utilization at different soil depths to improve and promote soil management in orchards. In this study, the stable hydrogen and oxygen isotope technique was used to study the characteristics of δD values (hydrogen isotope ratio) of the xylem water of apple trees, stem water of white clover and ryegrass, and soil water under different depths in different apple trees–grass intercropping systems (apple–white clover and apple–ryegrass) in the Luochuan Loess Tableland and to explore the effects of apple trees–grass intercropping systems on the water sources of apple trees and soil water use in different depths. The results showed that in May, white clover and ryegrass increased the water content in the 0 − 50 cm and 50 − 100 cm soil depths, respectively, with water originating from the 10 − 20 cm soil depths, and there was no water competition with fruit trees. White clover and ryegrass increased the water use efficiency of fruit trees in the soil below 40 cm by 27% and 9%, respectively. In July, the main water of the white clover and ryegrass originated from shallow and deep soils, with water competition with fruit trees. However, white clover experienced less competition with fruit trees than with ryegrass. White clover and ryegrass improved soil water use below 40 cm and 0 − 20 cm by fruit trees, respectively. In August and October, white clover increased the water content of the 0 − 50 cm soil depths and the utilization rate of the 0 − 40 cm soil water by fruit trees. Therefore, planting white clover could better adjust the water utilization level of fruit trees and the utilization rate of each soil level than ryegrass. Thus, fruit trees could absorb water to a greater extent. Results from this study provide a basis for understanding the driving mechanism of the water cycle in soil–plant systems, and guidance for forage variety selection and optimized water management of orchards in the Luochuan Loess Tableland.
Effects of six herbicides on toxic weeds in cultivated grasslands in the source region of the Yellow River
WU Jianli, WANG Xiaoli, SHI Jianjun, WANG Haibo, WANG Yanlong, WANG Chao, XING Yunfei
2021, 38(4): 738-748. doi: 10.11829/j.issn.1001-0629.2020-0292
[Abstract](2890) [FullText HTML] (868) [PDF 848KB](14)
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A 14-year-old cultivated grassland of Elymus nutans in Maqin County, Guoluo Prefecture, the source region of the Yellow River, was investigated. Pedicularis kansuensis and Ligularia virgaurea were the research objects. To control the main broad-leaved toxic weeds, six herbicides, individually and in five combinations, were tested. The six herbicides were 2, 4-D butyl ester (A), trituron (B), Longquan (C), Kono (D), Chakuo (E), and Tribenuron (F); and the five combination were 2, 4-D butyl ester and each other herbicide, namely, A + B, A + C, A + D, A + E, and A + F. Spraying B, F, and A + E reduced the height, cover, and biomass of L. virgaurea to varying degrees, and F and A + E had significant effects on biomass (P < 0.05). Spraying E, F, A + B, A + C, and A + F significantly reduced the height, cover, and biomass of P. gansuensis (P < 0.05), with A + F effectively controlling the toxic weed community. The highest control level was level 3. The cover and biomass of forages under A + E treatment were significantly higher than those of the control (P < 0.05). The species richness and Shannon-Wiener index of the herbicide-sprayed communities generally showed a downward trend. However, the uniformity index was slightly higher than in the control. The effects of the 11 treatments were evaluated using the fresh weight control effect, and the results showed that A + E, F, and A + F can control toxic weeds in cultivated grasslands in the source area of the Yellow River.
Mycoviruses in pastures and turfgrasses
WANG Shiyan, XIA Chao
2021, 38(4): 749-757. doi: 10.11829/j.issn.1001-0629.2020-0273
[Abstract](3284) [FullText HTML] (1581) [PDF 575KB](8)
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Mycoviruses are a group of viruses widely present in various fungi and oomycetes, wherein they complete their life cycles. Most mycoviruses cause no symptoms in their hosts, but some can cause hypovirulence and debilitation of their hosts. Hypovirulence-related mycoviruses have been detected in some grass pathogens including Helminthosporium victoriae, Rhizoctonia solani, and Fusarium graminearum. Recently, researchers discovered a mycovirus, CThTV, which could improve heat tolerance of the host, Curvularia protuberata, in a Dichanthelium lanuginosum–Curvularia protuberata symbiosis. Grass is the fundamental source of livestock feed and plays an essential role in terrestrial ecosystems. Grassland degradation and diseases have become increasingly severe, raising concerns about serious economic losses in the livestock industry. Here, we have systematically reviewed the definition and taxonomy of mycoviruses, their effects on the host, and the research status of mycoviruses, particularly in relation to pathogenic and endophytic fungi of grasses. We aimed to clarify the diversity and functions of mycoviruses, to facilitate mycovirus research and application in the field of grass-disease prevention and resistance improvement.
Effects of different dietary nitrogen to sulfur ratios on the jejunum tissue morphology and microflora of Tibetan lamb
YAN Xiaolan, HOU Shengzhen, LI Pengxiang, WANG Zhiyou, YANG Baochun, JIA Jianlei
2021, 38(4): 758-768. doi: 10.11829/j.issn.1001-0629.2020-0467
[Abstract](1710) [FullText HTML] (452) [PDF 1036KB](10)
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The intestinal tract of animals is an important digestive and absorbing organ. To investigate the effects of different nitrogen to sulfur ratios on jejunal morphology, microbial diversity, and function in Tibetan lambs, 150 Tibetan lambs aged 60 days old with similar initial conditions were randomly divided into 5 equal groups. Lambs were fed until 180 days of age on diets containing similar energy, with nitrogen to sulfur mass ratios of 10.5 ꞉ 1 (group A), 9 ꞉ 1 (group B), 7.5 ꞉ 1 (group C), 6 ꞉ 1 (group D), and 4.5 ꞉ 1 (group E). At the end of the experiment, 6 animals from each group were randomly slaughtered and then examined. The jejunum tissues and contents were collected to analyze the effects of dietary nitrogen to sulfur ratios on jejunum tissue morphology, microbial community structure, and function. The following results were noted: 1) The length and width of jejunum villi in groups B and E were significantly higher than the other three groups (P < 0.05), and the lengths of villi in groups A and D were significantly higher than that in group C (P < 0.05). The depth of crypts in group D was significantly higher in the other four groups (P < 0.05). The villus-length/crypt-depth quotient in groups B and E was significantly higher than in groups A, C, and D (P < 0.05). The mucosal layer thicknesses in groups B and E were significantly higher than in groups C and D (P < 0.05). The muscle-layer thickness in group B was significantly higher than those of other groups (P < 0.05). 2) The OTU and Chao1 indexes of the B and E groups were significantly higher than those of the A and C groups (P < 0.05). The Shannon indexes of the B and E groups was significantly higher than those of other groups (P < 0.05). The Simpson indexes of the C and D groups were significantly higher than those of groups B and E (P < 0.05). B, D, and E group Ace indexes were significantly higher than those of A and C groups (P < 0.05). 3) Analysis of community structure of the jejunal microbial flora at phylum and genus levels revealed that at the phylum level, the Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria predominate. Among them, the abundance of Firmicutes in group B was significantly higher than in group C (P < 0.05). The abundances of Actinobacteria in groups A and C were significantly higher than in groups B and E (P < 0.05). In groups B and E, the abundance of Bacteroidetes was significantly higher than in A and C groups (P < 0.05), and the abundance of Proteobacteria in group E was significantly higher than in groups B and D (P < 0.05). At the genus level, the four dominant bacterial genera were Rhodococcus, Brevibacterium, Christensenellaceae-R-7-group, Quinella, and Rikenellaceae-RC9-gut-group. The abundances of Rhodococcus in groups A, C, and D were significantly higher than in groups B and E (P < 0.05); the Christensenellaceae-R-7-group in group B was significantly higher than in all other groups (P < 0.05), and Quinella in groups A and B was significantly higher than in groups D and E (P < 0.05). 4) The PICRUSt function prediction results for the 16S rRNA genome show that the functions of the jejunal microbial flora mainly involve transcription and the transport and metabolism of carbohydrates and amino acids, indicating that Tibetan lamb jejunum bacteria can improve the host’s carbohydrate and protein metabolism and absorption. In summary, the nitrogen to sulfur ratio at B and D levels is beneficial to the development of jejunum tissue morphology in Tibetan lambs and increases the diversity and richness of the jejunum microbial flora. From an economic perspective, a nitrogen to sulfur ratio of 9 ꞉ 1 is most conducive to efficient raising of Tibetan lambs.
Growth law and growth curve fitting of Qianhua Mutton Merino
LI Jiarong, CHEN Yang, SUN Limin, JIANG Huaizhi, SHAN Xuesong, MA Long, MA Zhihua
2021, 38(4): 769-775. doi: 10.11829/j.issn.1001-0629.2020-0482
[Abstract](2355) [FullText HTML] (858) [PDF 683KB](18)
Abstract:
A new species in China, the Qianhua Mutton Merino is a breed of sheep that is farmed for both meat and wool. To understand the growth and development of Qianhua Mutton Merino sheep under indoor feeding conditions, the weights of rams and ewes aged 0~24 months were measured, and the results were subjected to fitting analysis using logistic and Gompertz models. The results showed that the degree of fitting R2 of the two models was above 0.95, with good fitting effects. The fitting effects of the Gompertz model were better than those of the Logistic model on body weight; the weight inflection point of rams and ewes were 6.37 months and 2.44 months, respectively, with a weight of 49.68 and 23.02 kg, and a maximum daily gain of 218.59 and 249.38 g·d−1, respectively; the weight of rams was significantly higher than that of the ewes at all ages. The absolute growth peaks of weight appeared in rams at 3~6 months and ewes at 0~3 months, which were consistent with the results of the growth model fitting. The results of this study provide a theoretical reference for establishing the early selection and breeding management strategies for the Qianhua Mutton Merino.
The regulatory effect and mechanism of choline on liver fat metabolism in dairy cows
LIU Zhejia, WANG Honghao, YAO Junhu, CAO Yangchun
2021, 38(4): 776-784. doi: 10.11829/j.issn.1001-0629.2020-0441
[Abstract](3447) [FullText HTML] (973) [PDF 756KB](9)
Abstract:
In the production and breeding process of the dairy industry, the prevention and control of nutritional metabolic diseases, such as fatty liver in perinatal dairy cows, is key to improved performance and production efficiency. Choline, an essential nutrient for animal growth and development, plays an important role in the regulation of liver fat metabolism. Proper dietary supplementation of choline can effectively reduce liver fat content, prevent fatty liver, and maintain the normal physiological function of the liver. Choline regulates lipid metabolism by up-regulating and down-regulating the expression of genes and proteins of the lipolysis and adipogenesis pathways, thus reducing fat deposition and alleviating fatty liver. In this study, the characteristics and functions of choline and its regulatory effect and mechanism on liver fat metabolism in dairy cows were reviewed. The study aimed to provide a theoretical basis for maintaining body health of dairy cows and improve ruminant production performance.
Emergy dynamic analysis of planting industry system in Gansu Province
YAO Yao, LI Guang, WANG Jun, LIU Qiang, LU Yulan
2021, 38(4): 785-795. doi: 10.11829/j.issn.1001-0629.2020-0264
[Abstract](2030) [FullText HTML] (573) [PDF 837KB](9)
Abstract:
To discuss the sustainable development of the planting industry in Gansu Province, the dynamic changes in energy input and output of the planting industry in the province from 2007 to 2017 were studied based on emergy theory. The results showed that both the total energy input and output of the planting industry in Gansu Province first increased and then decreased, with the energy input reaching a peak of 5.48 × 1022 sej in 2015 and the output reaching a peak of 2.55 × 1022 sej in 2014. Compared with the national planting industry, the annual mean values of net emergy yield ratio, emergy investment ratio, environmental load ratio, and emergy sustainable index of the planting industry system are lower in the Gansu Province, which are 0.71, 1.54, 1.50, and 0.48, respectively. It can be seen that the planting industry system in Gansu Province lacks vitality, has low development potential, and belongs to the unsustainable consumption economy system. Therefore, in the future development of Gansu province, we should improve the utilization rate of resources, reduce the input of non-renewable industrial auxiliary energy, pay attention to the protection of the ecological environment, and further promote the sustainable development of the planting industry.
Application of research-based teaching methods in the undergraduate Forage Seed Science Course
HU Xiaowen, HAN Yunhua, WANG Yanrong
2021, 38(4): 796-802. doi: 10.11829/j.issn.1001-0629.2020-0227
[Abstract](2850) [FullText HTML] (761) [PDF 475KB](22)
Abstract:
Research-based teaching is a new problem- and student-oriented teaching model which aims to improve students’ creative and practical abilities. It is an important way to meet society’s current needs for fostering innovative talent and students’ overall development. Taking the undergraduate teaching of the Forage Seed Science course at Lanzhou University as an example, this article focuses on optimization of teaching content, selection of research teaching topics, and the application of innovative teaching modes, methods and assessment. The article systematically discusses the potential value of applying research-based methods to the teaching of Forage Seed Science. Further, possible problems in the practical application of research-based teaching are discussed, and corresponding suggestions are proposed.