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Liu W.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Chen S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Hu F.,CAS Northwest Institute of Plateau Biology | Sha N.,Inner Mongolia Academy of Agricultural science
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012

Soil phosphorus (P) and potassium (K) are indispensable elements of plant growth, and their content change could affect biogeochemical cycles of carbon, nitrogen, and other elements. The study of spatial and vertical distributions of soil P and K is crucial for the sustainable development of alpine grassland. Further, it is critical to understand regional mechanisms of biogeochemical cycles of soil carbon, nitrogen, and other elements. Thirteen typical ecosystem plots (including seven soil types) were selected, and two or three soil profiles from each plot were investigated. This study occurred during the summers of 2010 and 2011 in the upstream of the Shule river basin on the northeastern margin of the Qinghai-Tibetan Plateau. Distributions of soil P and K, their influencing factors on topsoil (0-20 cm), and the soil profiles were studied. These elements were studied by analysis of soil P and K contents, other soil properties (such as soil organic carbon, total nitrogen, pH value, and so on), and meteorological factors (mean annual temperature and mean annual precipitation). The results showed that soil total P, available P, total K, and available K, contents in topsoil were (0. 50±0. 14) g/ kg (2. 69±1. 61) mg/ kg (14. 84±0. 59) g/ kg and (151. 03±117. 57) mg/ kg respectively. The correlation matrix of the variables showed that there were significant positive correlations between total P contents in the topsoil, mean annual temperature, and soil silt proportions. However, there was a significant negative relationship between total P contents in the topsoil and mean annual precipitation. Meanwhile, there were significant positive relationships between available P, soil organic carbon, and total nitrogen. There was a significant positive relationship between soil available K, soil silt content, and mean annual temperature. The densities of total P, available P, total K, and available K mainly concentrated in the 0-40 cm soil depth, and showed a decreasing trend with soil depth increase. Total P densities at different soil depths had a positive correlation with mean annual temperature, which increased with soil depth. Our study indicated that air temperature and precipitation were the main influencing factors for soil total P contents in topsoil and its spatial distribution. Because of similar soil parent material, small variances of total K in topsoil for the seven soil types were observed. The content of available P and available K contents could not meet plant growth need, and grassland management is an important factor for content change. Air temperature is the main control factor for total P and K densities in this study area. These results could provide fundamental data to clearly identify the P and K content status in alpine grassland soils. This, in turn, could provide new insights with which to understand the biogeochemical cycles and mechanisms of soil P, K, carbon, and nitrogen in alpine grassland ecosystems.

Huang Y.-J.,Rothamsted Research | Balesdent M.-H.,French National Institute for Agricultural Research | Li Z.-Q.,Rothamsted Research | Li Z.-Q.,Inner Mongolia Academy of Agricultural science | And 3 more authors.
European Journal of Plant Pathology | Year: 2010

To investigate whether the reported fitness cost of virulence at the AvrLm4 locus in Leptosphaeria maculans is common to other loci, near-isogenic (NI) isolates differing at AvrLm1 locus were produced in vitro. Fitness of virulent (avrLm1) or avirulent (AvrLm1) isolates on Brassica napus without the corresponding R (resistance) gene Rlm1 was investigated in controlled environment (CE) and field experiments. Results indicate that there is a measurable fitness cost for avrLm1 compared to AvrLm1 isolates in terms of number of lesions, size of lesions, distance grown through leaf tissue towards the petiole in CE experiments and systemic growth from leaf lesions to stems in field experiments. There were differences in fitness cost between the AvrLm1 and AvrLm4 loci. There was a cultivar effect on fitness cost of virulence at the AvrLm1 locus but not at the AvrLm4 locus. In CE experiments, the optimal temperature for leaf infection was greater for AvrLm4 isolates than for AvrLm1 isolates. Field experiment results suggest that on the same host AvrLm4 isolates are more fit than AvrLm1 isolates in warmer seasons. The fitness cost at the AvrLm4 locus was generally greater than at the AvrLm1 locus, suggesting that the corresponding R gene Rlm4 may be more suitable than Rlm1 for redeployment in commercial cultivars after an interval of a few years. © 2009 KNPV.

Xiang H.-Y.,China Agricultural University | Dong S.-W.,China Agricultural University | Zhang H.-Z.,Inner Mongolia Academy of Agricultural science | Wang W.-L.,China Agricultural University | And 4 more authors.
Virus Genes | Year: 2010

Beet western yellows virus (BWYV) has previously been reported as an agent of sugar beet yellowing disease in China. In this article, the complete genomic RNA sequences of two Chinese BWYV isolates infecting beet from Inner Mongolia (BWYV-IM) and Gansu (BWYV-GS) were determined and compared with three beet poleroviruses (BMYV, BChV and BWYV-US) and other non-beet-infecting poleroviruses. The genomes of the two isolates were 5,668 nt in length, and had almost the same genomic organization and characteristics as BWYV-US. The full length of BWYV-IM shared nucleotide sequence identities of 97.4, 86.6, 64.4 and 70.8% with BWYV-GS, BWYV-US, BChV and BMYV, respectively. Further sequence analysis indicated that the Chinese BWYV isolates were more closely related to BWYV-US; however, the identity of any gene product between the Chinese isolates and BWYV-US was <90%. Therefore, on the basis of genome sequence, we propose that these Chinese isolates are a distinct strain of BWYV that infect sugar beet. In addition, recombinant detection analysis revealed that BWYV-IM might be a recombinant virus. © 2010 Springer Science+Business Media, LLC.

Tang K.,Inner Mongolia Agricultural University | Yuan B.,Inner Mongolia Agricultural University | Yuan B.,Inner Mongolia Normal University | Lai Q.,Third Institute of Oceanography | And 3 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2015

A Gram-stain-negative, non-spore-forming, short rod-shaped, non-motile, light-pink bacterial strain, MIMtkLc17T, was isolated from biological soil crusts collected in Liangcheng, Inner Mongolia. Growth of strain MIMtkLc17T was observed at 2-35 °C and in the presence of 1% (w/v) NaCl. Phylogenetic analysis of 16S rRNA gene sequences showed that sequence similarities between strain MIMtkLc17T and the type strains of species of the genus Hymenobacter ranged from 89.93% to 96.49%. Strain MIMtkLc17T can secrete mass polysaccharide. The major fatty acids of strain MIMtkLc17T were iso-C15 :0, summed feature 3 (C16 :1ω7c/C16 :1ω6c), C16 :1ω5c and summed feature 4 (iso-C17 :1 I/anteiso-C17 :1 B). The sole respiratory quinone was menaquinone MK-7. The G+C content of the chromosomal DNA was 57.8 mol%. The results of phylogenetic, chemotaxonomic and phenotypic characterization indicated that strain MIMtkLc17T can be distinguished from all known species of the genus Hymenobacter and represents a novel species of this genus, for which the name Hymenobacter terrenus sp. nov. is proposed. The type strain is MIMtkLc17T (=MCCC 1K00507T=KCTC 42636T). © 2015 IUMS.

Yang N.,China Agricultural University | Pan X.,China Agricultural University | Zhang L.,China Agricultural University | Wang J.,China Agricultural University | And 7 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

Agriculture and pasture ecotone are typical ecologically vulnerable areas. Crop productivities and the agricultural sustainability are greatly affected by climate change in these areas. Field experiments were conducted from 2011 to 2013 in Inner Mongolia (41°06'N, 111°28'E) to investigate the influence of planting dates on yield and phenology of spring wheat and potential of improving resource (water and nitrogen) use efficiencies. The experimental field was located in arid and semiarid climate zone, where mean annual temperature was 2.7°C, annual growing degree days (>0) was about 2553 (°C·d), the average annual rainfall was only 354 mm mainly in July and August accounting for 80% precipitation in the whole growing season. Five sowing dates was designed from 26 April to 5 June with a 10-day interval. The results showed that the yields after 6 May were significantly (p<0.05) decreased due to delayed sowing dates. Compared to early sowing date (26 April), the yield of the late sowing date was reduced by 63.3% to 72.3% due to the obvious reduction in daily temperature from the growth stages of heading to maturity. Harvest index (HI) and grain weight per 1000 seeds were also affected by sowing dates. The early sowing (26 April and 5 May) treatments had higher HI. But after 16 May, the HI decreased significantly (p<0.05). The grain weight per 1000 seeds decreased from 44.65 to 20.73 g with the delaying of the seeding dates, which had a trend similar with HI. It indicated that low values of HI and grain weight contributed to yield decrease when sowing after 26 May. Phenology of wheat as expressed in calendar days were different between years and sowing dates, especially from sowing to emergency, but the phenology based on physiological development time (PDT) was similar with a constant value of 95.3 days (the days required to complete whole development stage at optimal temperature condition) between years and sowing dates. Water use efficiency (WUE) was significantly (p<0.05) decreased by delaying sowing dates. Compared with early sowing treatments, the WUE of late sowing dates were reduced by 68.8% to 74.3% probably due to the reduction of ratio of spike over above-ground dry matter in late sowing treatments (i.e. more vegetative growth and bigger canopy than early sowing treatments). Total nitrogen uptake by above-ground biomass ranged from 14.0 to 17.0 g/m2 for different sowing dates, however, the difference was not statistically significant (p>0.05). As the early sowing treatments showed higher (p<0.05) yield and HI, nitrogen use efficiency (NUE), the transformation of nitrogen uptake to the economic yield was significantly (p<0.05) higher in early sowing treatments than in late sowing treatments. Therefore, the best sowing date should be earlier than 6 May, and early sowing before 6 May could improve yield, water and nitrogen use efficiencies of wheat in the agriculture and pasture ecotone.

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