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Frontiers of agricultural Science and Engineering 2018年第1期5卷 148-158页

作者： Yuping ZHANG Yanfei ZHOU Xingxu ZHANG Tingyu DUAN Zhibiao NAN state key laboratory of Grassland Agro-ecosystem/College of pastoral agricultural Science and Technology Lanzhou UniversityLanzhou 730000China

Fungal endophytes of some cultivated grasses can increase plant performance and competitive abilities,especially under stress. Far less is known about the influence of Epichlo? infections in wild populations of wild grasses. In this study, plants of three Elymus dahuricus ecotypes(WLS, QY and WTS) either infected with Epichlo? endophyte(E+) or uninfected(E–) were grown in the field. The activities of the antioxidant enzymes ascorbate peroxidase, catalase, peroxidase and superoxide dismutase, and concentrations of H_2O_2 and malondialdehyde were examined in the leaves of E+ and E– plants. We also determined photosynthesis parameters,leaf blade and sheath carbohydrate concentration and plant growth parameters of both E+ and E– plants. E+ plants from the WLS and QY populations had significantly higher antioxidant enzyme activities and photosynthetic capability(P 0.05), and even displayed some negative effects on plant photosynthetic capability. Thus, endophyte infection significantly affected E. dahuricus antioxidant enzyme activities(P < 0.05), photosynthesis and growth capability,although, the effects varied with plant ecotypes.

关键词： antioxidant enzymes Elymus dahuricus Epichloë fungal endophyte photosynthesis

Effects of cadmium stress on seed germination and seedling growth of Elymus dahuricus infected with the Neotyphodium endophyte

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Science China(Life Sciences) 2012年第9期55卷 793-799页

作者： ZHANG XingXu LI ChunJie NAN ZhiBiao state key laboratory of Grassland Agro-ecoaystems College of Pastoral Agricultural Science and TechnologyLanzhou UniversityLanzhou 730020China

Various cadmium （Cd） concentrations （0, 50, 100, 200 and 300 μmol L-1） affected Elymus dahuricus seed germination, seed- ling growth, antioxidative enzymes activities （AEA）, and amounts of malondialdehyde （MDA） and proline present. These in- fluences were determined for separate E. dahuricus cohorts known to be either infected （E＋） or non-infected （E-） by a Neo- typhodium endophyte. Under high Cd concentrations （100, 200 and 300 lamol L-l）, E＋ specimens showed a significantly （P〈0.05） higher germination rate and index, as well as higher values for shoot length, root length and dry biomass. However, the germination rate and index, root length and dry weight did not show a significant （P〈0.05） difference under the low Cd concentrations （0 and 50 μmol L^-1）. AEA and proline content increased, as did MDA content, in the E＋（vs. E-） specimens under high Cd concentrations. There was no significant （P〉0.05） difference under low Cd concentrations. Endophyte infection was concluded to be of benefit to E. dahuricus exposed to high Cd concentrations.

关键词： cadmium Elymus dahuricus germination antioxidant enzyme endophyte

Paleoenvironmental implications of Holocene long-chain n-alkanes on the northern Bering Sea Slope

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Acta Oceanologica Sinica 2017年第8期36卷 137-145页

作者： ZHANG Haifeng WANG Rujian XIAO Wenshen laboratory of Marine ecosystem and Biogeochemistry State Oceanic Administration state key laboratory of Marine Geology Tongji University

The records of high-resolution terrestrial biological markers （biomarkers） from Core B2-9 from the northern Bering Sea Slope over the last 9.6 ka BP were presented in the study. Variations in input of terrestrial long-chain n-alkanes （referred to as n-alkanes） and vegetation structure in their source regions were investigated. The results show that the nCz7 is the main carbon peak and has the greatest contribution rate of the total n-alkane content; this might be related to the abundance of woody plants and their spatial distribution in the source region, nC23 is another n-alkane having a relatively high content; this was mainly derived from submerged plants widespread along the coastal areas in the northern hemisphere. Total n-alkane content dropped quickly at ca. 7.8 ka BP, ca. 6.7 ka BP and ca. 5.4 ka BP, and was followed by four relatively stable stages mostly controlled by sea-level rise, climate change and vegetation distribution in the source region. Variation in carbon preference index （CPI） indicates that the n-alkanes primarily originated from higher land plants, and the average chain length （ACL） and nCa1/nC27 ratio reveal the relatively stable presence of woody/herbaceous plants during the Holocene, and dominate woody plants in most of the time. Simultaneous variation in total n-alkane content, nC27 content and its contribution, CPI, ACL and nC31/nC27 ratio over several short periods suggest that the growth rate of the woody plant n-alkane contribution was lower than that of herbaceous plants and fossil n-alkanes under the particular climatic conditions of the source region.

关键词： Bering Sea terrestrial input long-chain n-alkanes vegetation structure Holocene

Mapping Daily Temperature and Precipitation in the Qilian Mountains of Northwest China

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Journal of Mountain Science 2014年第4期11卷 896-905页

作者： PENG Shou-zhang ZHAO Chuan-yan WANG Xiao-ping XU Zhong-lin LIU Xing-ming HAO Hu YANG Shi-fei state key laboratory of pastoral agricultural ecosystem Institute of Arid Agroecology School of Life Sciences Lanzhou University Institute of Arid Meteorology China Meteorological Administration MOE key laboratory of Oasis Ecology College of Resource and Environmental Science Xinjiang University Management Bureau of Qilian Mountains National Nature Reserve in Gansu

Daily meteorological data are the critical inputs for distributed hydrological and ecological models. This study modified mountain microclimate simulation model （MTCLIM） with the data from 19 weather stations, and compared and validated two methods （the MTCLIM and the modified MTCLIM） in the Qilian Mountains of Northwest China to estimate daily temperature （i.e., maximum temperature, minimum temperature） and precipitation at six weather stations from i January 2000 to 31December 2009. The algorithm of temperature in modified MTCLIM was improved by constructing the daily linear regression relationship between temperature and elevation, aspect and location information. There are two steps to modify the MTCLIM to predict daily precipitation： firstly, the linear regression relationship was built between annual average precipitation and elevation, location, and vegetation index; secondly, the distance weight for measuring the contribution of each weather station on target point was improved by average wind direction during the rainy season. Several regression analysis and goodness-of-fit indices （i.e., Pearson＇s correlation coefficient, coefficient of determination, mean absolute error, root-mean-square error and modelingefficiency） were used to validate these estimated values. The result showed that the modified MTCLIM had a better performance than the MTCLIM. Therefore, the modified MTCLIM was used to map daily meteorological data in the study area from 2000 to 2009. These results were validated using weather stations with short time data and the predicted accuracy was acceptable. The meteorological data mapped could become inputs for distributed hydrological and ecological models applied in the Qilian Mountains.

关键词： MTCLIM (Mountain microclimatesimulation model) Wind direction Precipitation Temperature Qilian Mountains.

Catalogue of Polychaete species(Annelida) described from China Seas during 2008–2017

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Journal of Oceanology and Limnology 2019年第2期37卷 724-735页

作者： WANG Yueyun WANG Chunsheng key laboratory of Marine ecosystem and Biogeochemistry Second Institute of Oceanography State Oceanic Administration

China Seas are one of the most diverse regions in the Pacific. Though much eff ort has been made to explore its biodiversity, the polychaetes diversity is still poorly known. A large number of species records are based on ecological investigation rather than taxonomical studies. We update the Polychaete species taxonomicaly described from China coastal waters during 2008–2017 and list them as a catalogue. The catalogue contains 47 species of 32 genera and 17 families, the type depository, type locality and geographic distribution. Some taxonomic problems are present in remarks.

关键词： checklist Annelida Polychaeta taxonomy China Seas

Effects of cutting frequency and height on alkaloid production in endophyte-infected drunken horse grass (Achnatherum inebrians)

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Science China(Life Sciences) 2011年第6期54卷 567-571页

作者： ZHANG XingXu LI ChunJie NAN ZhiBiao state key laboratory of Grassland Agro-systems College of Pastoral Agricultural Science and TechnologyLanzhou UniversityLanzhou 730020China

An evaluation was performed on the influence of mowing height (2.5,5.0 or 7.5 cm) and mowing frequency (weekly or fortnightly) on levels of ergot alkaloids (ergine and ergonovine) formed in drunken horse grass,Achnatherum inebrians,grown under greenhouse *** were taken monthly and alkaloids were extracted and analyzed by reverse-phase *** levels increased more or less linearly with plant age over the first four months following *** were higher in samples cut fortnightly compared to those cut weekly,and were higher when plants were cut at a mowing height of 7.5 cm vs.2.5 *** most cases,the highest alkaloid levels observed were almost three times those of the *** plant protection applications are developed for the endophytic fungus,Neotyphodium gansuense,it will be necessary to be aware of the potential role of plant husbandry practices (e.g.,defoliation frequency and intensity) for reducing or enhancing levels of plant *** husbandry factors may affect alkaloid levels in other Neotyphodium-grass associations,which would be interesting for further study.

关键词： Neotyphodium gansuense Achnatherum inebrians mowing height mowing frequency ergine ergonovine

Synonymous codon usage pattern in model legume Medicago truncatula

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Journal of Integrative Agriculture 2018年第9期17卷 2074-2081页

作者： SONG Hui LIU Jing CHEN Tao NAN Zhi-biao state key laboratory of Grassland Agro-ecosystems College of Pastoral Agriculture Science and Technology Lanzhou University Grassland Agri-husbandry Research Center Qingdao Agricultural University

Synonymous codon usage pattern presumably reflects gene expression optimization as a result of molecular evolution. Though much attention has been paid to various model organisms ranging from prokaryotes to eukaryotes, codon usage has yet been extensively investigated for model legume Medicago truncatula. In present study, 39 531 available coding sequences （CDSs） from M. truncatula were examined for codon usage bias （CUB）. Based on analyses including neutrality plots, effective number of codons plots, and correlations between optimal codons frequency and codon adaptation index, we conclude that natural selection is a major driving force in M. truncatula CUB. We have identified 30 optimal codons encoding 18 amino acids based on relative synonymous codon usage. These optimal codons characteristically end with A or T, except for AGG and TTG encoding arginine and leucine respectively. Optimal codon usage is positively correlated with the GC content at three nucleotide positions of codons and the GC content of CDSs. The abundance of expressed sequence tag is a proxy for gene expression intensity in the legume, but has no relatedness with either CDS length or GC content. Collectively, we unravel the synonymous codon usage pattern in M. truncatula, which may serve as the valuable information on genetic engineering of the model legume and forage crop.

关键词： codon usage gene expression Medicago truncatula natural selection optimal codon

Suppression of weeds and weed seeds in the soil by stubbles and no-tillage in an arid maize-winter wheat-common vetch rotation on the Loess Plateau of China

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Journal of Arid Land 2018年第5期10卷 809-820页

作者： YANG Mei ZHAO Yuxin YANG Huimin SHEN Yuying ZHANG Xiaoyan state key laboratory of Grassland Agro-ecosystems College of Pastoral Agriculture Science and Technology Lanzhou University

Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, high abundances of weeds in reduced tillage systems cause significant yield losses. In this study, we explored the effects of no-tillage and stubble retention on the number and density of weeds and weed seeds in a 12-year maize-winter wheat-common vetch rotation on the Loess Plateau. Four treatments including conventional tillage, no-tillage, conventional tillage＋stubble retention and no-tillage＋stubble retention were designed and applied. We found that no-tillage increased the number of weed species and weed density in most of the crops, while stubble retention decreased weed density in maize and tended to suppress weeds in both no-tillage treatments（no-tillage and no-tillage＋stubble retention）. No-tillage led to an increase in the number of weed species in the weed seedbank and tended to increase seed density during the spring growth of winter wheat, but it decreased seed density during post-vetch fallow. Stubble retention tended to reduce seed density during the spring growth of winter wheat and post-vetch fallow. We concluded that no-tillage can promote weeds in the experimental crop rotation, while stubble retention suppresses weeds in untilled fields. The combined effects of stubble retention and no-tillage on weed suppression varied among the three crops. Based on these results, we recommend stubble retention in untilled legume-crop rotations on the Loess Plateau to improve the control of weeds.

关键词： agricultural conservation practice crop rotation no-tillage rainfed soil soil seedbank stubble retention weed control

Physiological responses of Populus euphratica Oliv. to groundwater table variations in the lower reaches of Heihe River, Northwest China

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Journal of Arid Land 2012年第3期4卷 281-291页

作者： Yang ZHAO ChuanYan ZHAO ZhongLin XU YiYue LIU Yao WANG Chao WANG HuanHua PENG XiangLin ZHENG state key laboratory of pastoral agricultural ecosystem Institute of Arid Agroecology School of Life Science Lanzhou Uni-versity Lanzhou 730000 China MOE key laboratory of Oasis Ecology College of Resource and Environmental Science Xinjiang University Urumqi 830002China key laboratory of Western China's Environment Systems MOE Lanzhou University Lanzhou 730000 China

Riparian vegetation in the lower reaches of Heihe River serves important ecological functions. However, the riparian ecosystems have been constantly deteriorating in the past 30 years simply due to water interception for oasis agricultural irrigation in the middle reaches of the river. This study pays a particular attention to Populus eu- phratica Oily. forest because it is a dominant component of the riparian ecosystem in the lower reaches of Heihe River where the depth of groundwater table is the controlling factor in sustaining riparian ecosystems. To reveal leaf-related physiological responses of Populus euphratica Oliv. forest to groundwater table variations, we analyzed the relationships between the depth of groundwater table （DG） and three leaf-related parameters, i.e. leaf stomatal density （SD）, specific leaf area （SLA）, and stable carbon isotopic composition （6~SC）. Our results show that the relationship between DG and leaf SD is a bi-mode one shaped by both salt stress and water stress. That is, salt stress appeared in shallow groundwater conditions and water stress happened in deep groundwater conditions, and the thin layer around 2.7 m of DG is a stress-free layer. Leaf SD fluctuated according to the DG variation, first de- creased with increasing DG, then increased at depths ranging 2.7-3.7 m, and after a relatively stable plateau of SD at depths ranging 3.7-5.2 m, decreased again with increasing DG. Our results also show that SLA decreased ex- ponentially with increasing DG and foliar 6130 values are also strongly dependent on DG, further demonstrating that these two parameters are sensitive indicators of water stress. The exponential curve suggests that SLA is more sensitive to DG when groundwater table is shallow and 3 m seems to be a threshold beyond which SLA becomes less sensitive to DG. Foliar 613C becomes more sensitive when the groundwater table is deep and 7 m seems to be a threshold below which the 6130 signature becomes more sensitive to DG.

关键词： opulus euphratica Oily stable carbon isotopic composition stomatal density specific leaf area groundwater table

Exposure to difenoconazole inhibits reproductive ability in male marine medaka(Oryzias melastigma)

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Journal of Environmental Sciences 2018年第1期30卷 126-132页

作者： Xiaocui Dong Lemeng Zhang Meng Chen Zhibin Yang Zhenghong Zuo Chonggang Wang state key laboratory of Cellular Stress Biology School of Life Sciences Xiamen University key laboratory of Ministry of Education for Subtropical Wetland ecosystem Research Xiamen University

Difenoconazole（DFZ） is a triazole fungicide which has been detected in the aquatic environment, including estuaries and embayments. However, few studies addressing the reproductive toxicity and transgenerational effects of DFZ on marine fishes are *** present study was conducted to investigate the effects of DFZ on male marine medaka（Oryzias melastigma）. After exposure of the embryo to 1, 10, 100 and 1000 ng/L DFZ for180 days, the gonadosomatic index was significantly decreased in the 1000 ng/L *** number of sperm was reduced while the abundances of spermatocytes and spermatogonia in the testes were increased in all the treatments. The m RNA levels of salmontype gnrh（sgnrh）, the luteinizing hormone（lhβ） and the follicle-stimulating hormone（fshβ）genes in the brain all exhibited a significant down-regulation, the expression of androgen receptors（arα and arβ） was decreased and that of estrogen receptor β and cytochrome P450 aromatase（cyp19 B） was increased in the testes. The expression levels of cyp19 A and cyp19 B were increased in the liver. The decrease of ars m RNA levels might be one of the reasons causing the reduction of sperm. The down-regulation of sgnrh, lhβ and fshβ m RNA levels suggested that DFZ might impact the spermatogenesis via the brain–pituitary–gonad pathway. The decrease of the fertilization success, the hatch ability and the swim-up success in the F1 generation indicated that DFZ pollution at environmental levels might cause a decrease of wild fish populations.

关键词： Difenoconazole Brain-pituitary-gonad axis Reproductive toxicity Marine medaka