State Key Laboratory of Grassland Agro Ecosystems

Lanzhou, China

State Key Laboratory of Grassland Agro Ecosystems

Lanzhou, China
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Xu S.,State Key Laboratory of Grassland Agro Ecosystems | Christensen M.J.,State Key Laboratory of Grassland Agro Ecosystems | Li Y.,State Key Laboratory of Grassland Agro Ecosystems
European Journal of Plant Pathology | Year: 2017

A series of studies were carried out on Colletotrichum lentis which had been been identified in 2015 based largely on the distinctive shape of conidia and ITS sequences, and which has been causing severe anthracnose disease symptoms on common vetch plants (Vicia sativa) in Gansu Province in the northwest region of China. A key focus of the present studies was to determine how vetch crops become infected. The addition of residues from harvested common vetch crops to land being prepared as a seedbed was shown to result in the highest levels of disease severity indicating that this management practice was the most likely way for crops to become severely infected. Seed transmission was unlikely to be the cause of severe outbreaks as less than 5% of seeds harvested from severely infected plants carried C. lentis. To verify that the species causing the severe outbreaks of anthracnose disease of vetch crops was C. lentis, sequence analysis of the ITS, TUB2, ACT, HIS3 and GAPDH genes was conducted. C. lentis isolates from common vetch and lentil (Lens culinaris) formed a distinctive group among Colletotrichum species, including those species that infect other forage and field crops. The unique shape of conidia of C. lentis, straight with only one end curved, was confirmed as being reliable for rapid identification of disease outbreaks caused by this damaging fungal pathogen. © 2017 Koninklijke Nederlandse Planteziektenkundige Vereniging

LI Z.,Lanzhou University | LI Z.,State Key Laboratory of Grassland Agro ecosystems | ZHANG Q.,Shandong Institute of Agricultural Sustainable Development | YANG Q.,Lanzhou University | And 8 more authors.
Journal of Agricultural Science | Year: 2017

Winter wheat (Triticum aestivum L.) production on the Loess Plateau in China has been threatened by water scarcity and climate change during the last decade. Sustainable crop production in this region requires managerial practices that can provide high yield and high water productivity (WP). A 7-year (2001–2008) study at the Loess Plateau Research Station of Lanzhou University investigated the effects of various conservation tillage practices on grain yield, soil water content (SWC), WP and economic return of winter wheat production. Tillage treatments included: conventional tillage (T), conventional tillage followed by stubble retention (TS), no-till (NT) and no-till followed by stubble retention (NTS). Over the entire experimental period, grain yield and WP of winter wheat ranged from 1279 to 4894 kg/ha and 0·32 to 2·41 kg/m3, respectively. Both were significantly affected by tillage treatment and year, while SWC was only affected by year. Grain yield and WP in TS was increased by 4·9, 12·1, 0·9% and 13·7, 20·4 and 3·9% compared with NTS, NT and T, respectively, over seven growing seasons. Additionally, a multiple linear regression analysis indicated that grain yield is mainly limited by SWC during planting. Despite its lower grain yield, the NTS treatment increased economic benefit by US$ 328, US$ 23 and US$ 87/ha compared with TS, NT and T, respectively. Therefore, it is suggested that increasing soil water storage at wheat sowing time and encouraging the use of NTS could improve economic returns in this region. Copyright © Cambridge University Press 2017

Gao P.,State Key Laboratory of Grassland Agro Ecosystems | Duan T.-Y.,State Key Laboratory of Grassland Agro Ecosystems | Christensen M.J.,State Key Laboratory of Grassland Agro Ecosystems | Nan Z.-B.,State Key Laboratory of Grassland Agro Ecosystems | And 3 more authors.
European Journal of Plant Pathology | Year: 2017

We studied the development of rust disease, and biochemical and physiological responses, on Apocynum venetum plants inoculation with Melampsora apocyni that were growing in a greenhouse at four relative soil water contents. The soil conditions were 25% (severe drought), 50% (mild drought), 75% (optimal) and 100% (waterlogging) relative soil water content. Plants exposed to drought and waterlogging stress had a lower number of open stomata before inoculation, corresponding with the disease index on the 10th day after inoculation being lower than that of the optimal soil water condition. Inoculated plants exposed to severe and mild drought stress had a gradually enhanced resistance to the rust disease from the 10th day after inoculation, corresponding with the enhanced activity of polyphenol oxidase and phenylalanine ammonialyase. For the inoculated plants exposed to severe drought stress, hydrogen peroxide always remained at the highest level for any treatment, and they had a rapidly enhanced activity of peroxidase, two factors that were associated with suppression of disease development. A. venetum plants exposed to double stress of waterlogging and disease had a high activity of peroxidase that not only removed reactive oxygen to prevent or reduce cell injury but also enhanced resistance to the rust disease. In addition, a rapidly enhanced activity of phenylalanine ammonialyase in the waterlogging condition from the 25th day after inoculation was also associated with an enhanced resistance to the rust disease. Drought and waterlogging stress had a negative effect on the leaf photosystem, and in particular, there was a significant decrease in the net photosynthetic rate with an increase in the duration and degree of drought stress, and this lead to a statistically significant decrease in the weight of aboveground tissue compared with that of plants under optimal soil water condition (P < 0.05). Inoculating with M. apocyni had a slight effect on photosynthesis of plants during early disease development, but the physiological function of diseased leaves under the drought stress was damaged more seriously than that of non-inoculated plants in later disease development, leading to a large reduction in the net photosynthetic rate. However, this reduction did not cause a statistically significant (P > 0.05) decrease in the weight of aboveground tissue compared with that of non-inoculated plants under drought stress. © 2017 Koninklijke Nederlandse Planteziektenkundige Vereniging

Zhang R.,State Key Laboratory of Grassland Agro ecosystems | Zhang R.,Lanzhou University | Wang Y.R.,State Key Laboratory of Grassland Agro ecosystems | Wang Y.R.,Lanzhou University | And 6 more authors.
Seed Science Research | Year: 2016

The fruit plus accessory parts, and thus not only the fruit or seed, is the diaspore in some species of flowering plants. Atriplex centralasiatica, a summer annual salt-secreting cold-desert halophyte of central Asia that produces flat and humped diaspores, is such a species. The dispersal/germination units of this diaspore-heteromorphic species are fruits enclosed in persistent ‘bracteoles’. Germination of black and brown fruits (i.e. ‘bracteoles’ removed) of this species has been studied in some detail previously, but little attention has been given to the germination biology of the intact diaspores. The aim of this study was to compare the germination biology of the intact diaspores of A. centralasiatica, and their fates in the field during 12 months on the soil surface and buried at 5-cm depth. Fresh flat diaspores germinated to 42.7–51.3% in light (12-h photoperiod) and to 16.0–59.3% in constant dark, over a temperature range of 15–20/30°C, while no freshly matured humped diaspores did so under any temperature/light regime. Neither gibberellin (GA3) nor potassium nitrate (KNO3) had an effect on germination of either diaspore. Both diaspores readily imbibed water, and removal of ‘bracteoles’ released most of the dormancy. Thus, the ‘bracteoles’ are primarily responsible for diaspore dormancy in A. centralasiatica. Humped diaspores persisted for a longer period in the soil than flat ones. The germination requirements of intact natural dispersal/germination units of A. centralasiatica differ from those previously reported for fruits of this species. Copyright © Cambridge University Press 2016

Wen Z.,State Key Laboratory of Grassland Agro Ecosystems | Wen Z.,Lanzhou University | Wen Z.,Central Laboratory of Technical Center | Duan T.,State Key Laboratory of Grassland Agro Ecosystems | And 5 more authors.
Biocontrol Science and Technology | Year: 2015

Medicago sativa L. is the most important forage legume in China. Reducing production losses caused by disease is an essential aspect of maximising alfalfa production. In the current study a Fusarium semitectum isolate collected from alfalfa roots exhibiting symptoms of root rot was proven to infect alfalfa by fulfilling Koch's postulates. A bacterial strain, MB29, also collected from alfalfa roots, was evaluated as a potential biocontrol agent against F. semitectum and a range of other alfalfa pathogens using in vitro tests. It was found that MB29 reduced the mycelia growth of all the pathogens assessed, and in the case of F. semitectum by as much as 84.47%. Furthermore, in vivo test showed that MB29 reduced the severity of rot symptoms in alfalfa seedlings resulting from F. semitectum infection. Strain MB29 was subsequently classified as Bacillus subtilis subsp. spizizenii using the Biolog MicroLog microbial identification system and sequence analysis of its 16S rDNA gene. Taken together these results indicate that B. subtilis subsp. spizizenii MB29 has great potential for the control of root rot diseases in alfalfa. © 2015, © 2015 Taylor & Francis.

Zhang W.,State Key Laboratory of Grassland Agro ecosystems | Hu M.,Chinese Academy of Sciences | Liu G.,Chinese Academy of Sciences | Gao Z.,Chinese Academy of Sciences | And 2 more authors.
European Journal of Plant Pathology | Year: 2014

Red thread caused by Laetisaria fuciformis and pink patch caused by Limonomyces roseipellis often occur on many cool-season turfgrass species in temperate regions throughout the world. Incidences of L. fuciformis causing red thread on seashore paspalum (Paspalum vaginatum) and Li. roseipellis causing pink patch on hybrid bermuda grass (Cynodon dactylon × C. transvaalensis) have been reported as new diseases in Hainan Province, a Chinese island with a tropical climate. Field investigations were carried out at 14 golf courses and three college lawns in six cities of Hainan Province from April 2011 to April 2013. Red thread disease was observed on four warm-season turfgrasses throughout the period in all six cities, while pink patch was found on two warm-season turfgrasses in three cities. A total of 21 red thread isolates and five pink patch isolates were collected from these infected turfgrasses. These isolates were identified based on morphological and culture characteristics as well as nucleotide sequences from partial mitochondrial small subunit ribosomal RNA (mtSSU) and nuclear large subunit ribosomal RNA (nuLSU) genes. The optimal temperature for hyphal growth was either 25 or 28 °C for red thread isolates and 28 °C for pink patch isolates. The growth rate of all isolates was significantly less when cultures were grown under continuous light compared to the 12 h light/12 h dark or 24 h dark regimes. Arthroconidia production was optimized under the 12 h light/12 h dark regime. Selected fungal isolates were tested for pathogenicity by inoculating on ‘Seaspray’ seashore paspalum, ‘Princess 77’ bermuda grass (Cynodon dactylon), and ‘Lanyin No 3’ japanese lawngrass (Zoysia japonica) under controlled environmental conditions. All tested L. fuciformis and Li. roseipellis induced foliar blight in the turfgrass species. © 2014, Koninklijke Nederlandse Planteziektenkundige Vereniging.

Yang Q.,State Key Laboratory of Grassland Agro ecosystems | Yang Q.,Lanzhou University | Wang X.,State Key Laboratory of Grassland Agro ecosystems | Wang X.,Lanzhou University | And 2 more authors.
Journal of Soil Science and Plant Nutrition | Year: 2013

The effects of long term no-till and crop residue on soil microbial community catabolic function and relevant carbon cycle in the rhizosphere and bulk soils were assessed in the 10th year of a maize-winter wheat-soybean crop rotation. Conventional and zero tillage were coupled with residue removal and residue retention in a factorial design. Soil microbial community catabolic diversity was determined using Biolog-Eco plate. Average well colour development value (AWCD) of the microbial community in the rhizosphere soil was significantly higher than that in the bulk soil. Soil organic carbon (SOC) and microbial biomass carbon (MB-C) content of rhizosphere soil under both zero tillage and residue removal treatments were significantly higher than those in the bulk soil. Microbes in bulk soil presented a preferential utilization of diverse carbon sources when crop residue was retained. Zero tillage significantly increased the utilization of most carbon sources of microbial in the rhizosphere compared to conventional tillage. Principal component analysis (PCA) of the distribution of carbon substrate utilization for all treatments suggests that the microbial community catabolic diversity is different between the tillage management treatments and between soil sampling positions. Effects of zero tillage and crop residue retention were different with respect to the microbial catabolic diversity in the rhizosphere and the bulk soil.

Yang Q.,State Key Laboratory of Grassland Agro ecosystems | Yang Q.,Lanzhou University of Technology | Wang X.,State Key Laboratory of Grassland Agro ecosystems | Wang X.,Lanzhou University of Technology | And 3 more authors.
Soil Science and Plant Nutrition | Year: 2013

This study reports the effects of a long-term tillage and crop residue experiment on the soil microbial ecology of a Loess soil located in Gansu Province, western China. Tillage and residue management treatments were imposed on a nine-year continuous rotation of maize (Zea mays L. cv Zhongdan No. 2), winter wheat (Triticum aestivum L. cv Xifeng No. 24) and soybean (Glycine max L. cv Fengshou No. 12). After nine years, there were significant effects on topsoil (0-10 cm) carbon, nitrogen, microbial activity, microbial composition and function. The retention of crop residues compared to residue removal significantly improved all measures of chemical and biological soil fertility. The values of average well color development (AWCD), a measure of the metabolic utilization of organic compounds, for the residue retention treatments were always higher than those with residue removal treatments, and the differences increased with increasing incubation time. Principal component analysis indicated that crop residue retention significantly altered topsoil microbial activity and community functional diversity. Our research clearly demonstrates that retention of crop residues significantly enhances soil microbial metabolic capacity, compared to no tillage, and can therefore contribute to sustainable agriculture on the Loess Plateau. Promotion of conservation agriculture has the potential to rehabilitate soil fertility and improve agricultural sustainability and food security on the region. © 2013 Copyright Japanese Society of Soil Science and Plant Nutrition.

Tian L.H.,State Key Laboratory of Grassland Agro ecosystems | Tian L.H.,Lanzhou University | Bell L.W.,CSIRO | Shen Y.Y.,State Key Laboratory of Grassland Agro ecosystems | And 2 more authors.
Crop and Pasture Science | Year: 2012

Conventional rainfed mixed croplivestock systems of western China lack high-quality forage and restrict livestock production. This study explored the forage potential from wheat and its effects on subsequent grain yield. Different cutting times were imposed on winter wheat (Triticum aestivum) at Qingyang, Gansu Province, in two growing seasons, and the effect of nitrogen (N) topdressing rates (0, 60, and 120kgN/ha) on grain yield recovery was explored. Results showed the potential to produce 0.81.6tDM/ha of wheat forage with high nutritive value when cut before stem elongation (GS 30). In the wetter year, cutting before stem elongation did not delay crop development significantly (3 days at anthesis and 5 days at maturity), but grain yields were reduced by 1728% compared with the uncut crop (5.8tDM/ha), mainly due to reductions in number of spikes per m2 and, consequently, number of grains per m2. In both seasons, more forage biomass was available if crops were cut later than GS 32, but this came with large reductions (62%) in grain yield and delays in crop development (9 days or 131 degree-days). Crops cut later than GS 30 had greatly reduced harvest index, tillers per m2, and total N uptake but higher grain protein content. There was no significant effect of N topdressing rate on grain yield, although provided the crop was cut before GS 30, higher rates of N increased maturity biomass and crop N uptake by replacing N removed in cut biomass. This study showed that physiological delay of wheat due to cutting was not significant. The forage harvested from winter wheat before stem elongation could be a valuable feed resource to fill the feed gap in western China. Journal compilation © CSIRO 2012.

Yu B.H.,Lanzhou University | Yu B.H.,State Key Laboratory of Grassland Agro ecosystems | Nan Z.B.,Lanzhou University | Nan Z.B.,State Key Laboratory of Grassland Agro ecosystems | And 4 more authors.
Crop and Pasture Science | Year: 2012

Yellow stunt and root rot caused by Embellisia astragali are major factors contributing to declining yields of standing milkvetch (Astragalus adsurgens). The resistance of ten varieties of standing milkvetch to E. astragali was evaluated under laboratory, greenhouse, and field conditions. Seed germination/emergence, shoot and root length, plant dry weight, disease incidence, mortality, and disease severity index were monitored. The results show that Shanxi and Zhongsha No. 1 varieties had the best agronomic traits and lowest levels of disease in all experiments, while the varieties Neimeng and Ningxia had the highest susceptibility to disease. Germination/emergence differed significantly (P<0.05) between varieties after inoculation, and compared with the control, germination/emergence of inoculated treatments of nine varieties decreased on average by 1.5% in laboratory experiments and by 4.1% in greenhouse experiments at 15 days after inoculation. Inoculation reduced shoot length by an average of 24.4% and 41.5% (P<0.05) in laboratory and greenhouse experiments, respectively, in six of ten varieties. All varieties showed significantly (P<0.05) lower plant dry weight following inoculation, with reductions ranging from 0.3 to 0.6mg in the laboratory and from 82.6 to 149.4mg in the greenhouse. Resistance to the pathogen was evaluated on the basis of disease incidence, a disease severity index (DSI), and mortality; varieties showing different resistance were grouped using cluster analysis. There were significant correlations between the results of laboratory and greenhouse experiments (r=0.79; P<0.01) and between greenhouse and field experiments (r=0.83; P<0.01) across all varieties. Multiple regression analysis between laboratory/greenhouse and field experiments on DSI suggested that screening in the laboratory/greenhouse could be an alternative method of rapidly estimating DSI under field conditions. © 2012 CSIRO.

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