Table of Content

20 August 2011, Volume 20 Issue 4

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Effects of long-term conservation tillage on soil physical quality of rainfed areas of the Loess Plateau

ZHANG Ren-zhi, LUO Zhu-zhu, CAI Li-qun, HUANG Gao-bao, LI Ling-ling, XIE Jun-hong

2011, 20(4):  1-10. 

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Long-term field experiments on soil physical quality in rainfed farming systems were conducted in Dingxi on the western Loess Plateau. The effects of conventional tillage and five conservation agriculture patterns [conventional tillage (T), conventional tillage with stubble incorporation (TS), no till with no stubble (NT), no till with stubble retention (NTS), conventional tillage with plastic mulching (TP) and no till with plastic mulching (NTP)] were studied. The experiment was fully-phased with two rotation sequences. Phase 1 started with field pea (Pisum sativum) followed by spring wheat (Triticum aestivum) (P→W) whereas phase 2 started with spring wheat followed by field pea (W→P). There were highly significant differences between the six tillage measures in soil properties including soil aggregates, available water content, water use efficiency and saturation conductivity. There were also significant differences in some soil properties including soil bulk density, total porosity, capillary porosity, non-capillary porosity, soil strength and saturation capacity. There were no significant differences in soil properties such as soil temperature and field capacity. Using the addition and multiplication method, and weighted integrated method, quantitative assessments of soil physical quality in different tillage systems were carried out. The order of soil physical quality index from high to low was NTS, NTP, NT, TS, T(TP) and TP(T) in P→W rotation, and NTS, NTP, TS, NT, TP and T in W→P rotation. The various tillage measures resulted in very different soil physical quality levels. Improved soil structure arose from tillage reduction or residue retention which improved soil structure, enhanced water infiltration, reduced soil and water loss, and hence improved soil physical quality.

Analysis of the change of carbon storage in alpine arid grassland

ZHANG Fan, QI Biao, WEN Fei, ZHANG De-gang, WU Hong, ZHANG Li

2011, 20(4):  11-18. 

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The different change of organic carbon contents of the 0-10, 10-20, 20-30, 30-40 cm soil layers were studied on based on seven different alpine meadow -use types, which were serious degraded (SD), heavy degraded (HD), moderate degraded (MD), light degraded (LD), non-degraded (ND), fenced-ungrazed (FUG) and artificial-pasture (AP), in the northeastern of Qinghai Lake Region. The storage of soil organic carbon per unit area varied in the order of LD>ND>MD>HD>AP>FUG>SD in the May to July, in the order of ND>LD>MD>HD>FUG>AP>SD in the August to October, the soil organic carbon in the fenced-ungrazed and artificial-pasture was significantly (P<0.05) lower than that in lightly degraded and non-degraded, no significant difference was found between in the fenced-ungrazed and artificial-pasturer (P>0.05). From 0-10 to 30-40 cm soil layers, the storage of soil organic carbon per unit area varied in the order of 0-10>10-20>20-30>30-40 cm and was significantly (P<0.05). In different months, the carbon storage decreased dramatically from May to June and increased from July to October.

Dynamic of phosphorus with wheat-soybean rotation systems under conservation tillage in the western Loess Plateau

ZHENG Li-na, WANG Xian-zhi, SHEN Yu-ying

2011, 20(4):  19-26. 

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The research presented crop yield, phosphorus dynamic for a wheat-soybean rotation systems affected by tillage management: conventional tillage (t), tillage+stubble retention (ts), no-till (nt), no-till+stubble retention (nts) in the Loess Plateau. Results showed that ten years tillage management implementation did not carry a yield penalty for winter wheat, soybean yield had a positive response to conservation tillage. Soil phosphorus content increased with the increasing of rotation sequences. Both total phosphorus and available phosphorus contents were increased at top 0-5 cm. Stubble retention increase crop phosphorus uptake, P contents in soybean grain under nts and ts treatnment were 111% and 82% higher than that under t treatment. The results provide a local agricultural implement provides certain theoretical guidance.

Phospholipid fatty acid analysis of microbial community structure under different land use patterns in soil ecosystems of Leymus chinensis steppes

ZOU Yu-kun, ZHANG Jing-ni, YANG Dian-lin, CHEN Xiu-rong, ZHANG Tian-rui, ZHAO Jian-ning, ZHAO Shuai

2011, 20(4):  27-33. 

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Effects of different land use patterns on the structure of microbial communities of the Leymus chinensis steppe soil ecosystems were studied by phospholipid fatty acid analysis. Soil microbial community structure changed under different land use patterns. Microbial characterization of the total PLFA content of mown plots was significantly higher than those of the fenced and grazed plots, and total PLFA content of the fenced plots was the lowest. Correlation analysis showed that the total concentration of PLFA was significantly positively correlated with microbial biomass carbon as determined by the fumigation-extraction method. Mowing significantly increased both soil bacterial content and actinomycete content of fenced plots but soil fungal content was not significantly affected under different land use patterns. Bacterial characterization of PLFA in mown plots was the highest (29.6 nmol/g, bacterial contents) with grazed and fenced plots at 27.8% and 49.3% respectively. Dominant PLFA type of mown plots were a15:0, 15:0, 16:0 and 18:0, and accounted for 64.6% of total PLFA; Dominant PLFA type of grazed plots were i15:0, i16:0 and 18:1ω9t, and accounted for 45.6% of total PLFA; Dominant PLFA type of fenced plots were a15:0,15:0 and i16:0, and accounted for 46.3% of total PLFA.

Studies on crop coefficients of typical steppe in Inner Mongolia

HOU Qiong, WANG Ying-shun, SHI Gui-hua, YANG Ze-long

2011, 20(4):  34-41. 

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Based on data of field water experiments on typical steppe of Inner Mongolia in 2008, a crop coefficient of the typical steppe was calculated from analysis of the water amount balance, and changing regularity during the growing season. Simulation equations of the crop coefficient built with number of days after grass revival in a year and accumulated temperature above 0℃, showed that simulation using a cubic polynomial expression was appropriate and correlation coefficients were all over 0.94. Typical values of crop coefficients were defined with a linear section method of FAO, and they were 0.43 in the initial growing period, 1.02 in the medium growing period and 0.90 in the final stage. A method of revising the crop coefficient of typical steppe under stress conditions was put forward with leaf area index (LAI). The crop coefficient given in this article was suitable for typical steppe in Inner Mongolia, because simulating calculation of soil water was mostly close to the results of actual observations with mean relative simulation errors of 6.2%-13.6%.

Simulating and analyzing dynamic changes of potential vegetation in arid areas of Northwest China

LI Fei, ZHAO Jun, ZHAO Chuan-yan, WANG Xu-feng

2011, 20(4):  42-50. 

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The potential vegetation, as a final state of succession which achieves the balance with its site, is the most stable and mature climax vegetation type at the site without human interference. The ecological and environmental problems of the northwest arid area are very serious. Taking the potential vegetation as the reference for showing backgrounds of vegetation and rules of change has become the preliminary and infrastructural work towards ecological construction in arid areas of Northwest China. Based on the integrated sequence classification (IOCSG) and the support of GIS, this paper simulates distribution of vegetation, and analyzes dynamic changes in the study area. 1) Using the IOCSG model in arid areas of Northwest China, the accuracy of potential vegetation simulated reached 78%. 2) There were 21 potential vegetation types distributed in the study area. The diversity of vegetation in different regions was quite different. Vegetation was abundant in Tianshan, Altai, Daxinganling. In contrast, in the Junggar Basin, Tarim Basin, and Badain Jaran desert, the distribution of vegetation was relatively simple, mainly in desert and semi-desert. 3) As climate and environment change at a site, the regional vegetation system shows instability. There are four typical variation patterns, i.e. increasing change, reducing change and disappearing and fluctuating vegetation. 4) Complicated processes of succession of the potential vegetation happened because of changes in climatic and environmental adaptability at the site. In Tianshan, Altai, Daxinganling, to the west of Daxinganling and Hulunbeier, successions of the potential vegetation are more significant.

Study of patches community diversity on salinization grassland in north of Shanxi province

ZHAO Xiang, XIE Kai-yun, WANG Yan-jun, DONG Kuan-hu, ZHU Hui-sen

2011, 20(4):  51-60. 

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8 communities patches on salinization grassland were studied by the dominance, diversity and community characteristics.The purpose of this paper was reveal to the structure and variation of grassland community patches in the succession process, further provide the theoretical basis to grassland restoration and salinization grassland restoration. The results showed that the species composition and dominance of 8 community patches were more obvious different, the Margalef species richness index and Shannon-Wiener diversity index were significant different between the patchⅡ,Ⅲ and Ⅰ,Ⅳ,Ⅴ,Ⅵ,Ⅶ,Ⅷ (P＜0.01), the Simpson dominance index and Pielou uniformity coefficient were significant different between the patches Ⅱ,Ⅲ and Ⅵ,Ⅶ,Ⅷ(P＜0.01), the community similarity coefficients of the patch Ⅶ and Ⅷ, Ⅵ and Ⅶ, ⅣandⅤ were largest, respectively 0.956 7, 0.929 7, 0.903 4. There were two groups of community patches. Patch Ⅰ,Ⅱand Ⅲ were a groups, which soil moisture, bulk density, pH value and salinity were lower, the dominant plant is Leymus secalinus. With the drying of soil, some weak drought-resistant species disappeared from the community, while drought-resistant L. secalinus occupied dominant status in the group patches, there becomed community patches which dominant plant was L. secalinus. Others were in another group, the dominant plants were Potentilla anserina and Casuarina cunninghamiana.

A study on the plot minimum area and shape for sampling Trollius chinensis yield

LI Yong-ning, MA Kai, HUANG Xuan-ri

2011, 20(4):  61-69. 

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A sample survey is an important method for investigating plant resources. Plot area and shape underlie sampling surveys and influence survey efficiency and accuracy. To determine optimum plot area and shape for investigating yield of Trollius chinensis, three plot shapes (square, rectangle and circle) with a range of side lengths or radii were used to fit the CV (coefficient of variation)-area curve by the Generalized Mitscherlich equation, Richard equation and Logistic equation. Two methods were put forward for determining plot minimum area, one was based on CV change rate, the other on minimum investigating cost. The optimum plot shape was obtained by also comparing plot shape. The three CV-area models were all pretty good and the correlation coefficient was above 0.94, with Logistic equation the most stable. The minimum plot area estimated by change rate was in the order Richard equation>Logistic equation>Generalized Mitscherlich equation for the same plot shape, and was circle>square>rectangle for the same regression equation: the areas of squares and rectangles were similar. The study also showed that the minimum investigation cost was close for the same plot shape and different regression models, but the minimum plot area varied. For the same regression equation, the minimum plot area based on minimum plot cost was circle>square>rectangle while the square and the rectangle were also similar. Finally and comprehensively, the minimum plot area of square, rectangle, and circle were determined as 36 m² (6 m×6 m), 32 m² (8 m×4 m), 78.5 m² (radius 5 m) respectively. The optimum plot shape was obtained from the minimum CV of plots of different shapes, cost of the same area plots and comparisons among regression models. The rectangular plot was the best followed by the square with little difference between them. The circle was the worst shape.

Distribution patterns of nutrients in different positions of 5 oat varieties at different breeding periods

WANG Tao, XU Chang-lin, ZHANG Li-jing, ZHOU Zhi-yu

2011, 20(4):  70-81. 

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Nutrient content and caloric value of stems, seeds, leaves, and whole-plant of five species of excellent oats (Avena sativa) planted in an alpine meadow area of Tianzhu were studied at heading stage, milking stage and mature stage. EE contents in stems, seeds, and whole-plant of Avena sativa cv.No.4617 at maturity were significantly higher than at the milking, water-soluble sugar content and caloric value at the milking stage were significantly higher than at the heading stage and mature stage. CP (crude protein) contents in stems, leaves and whole-plant of A. sativa cv.Qingyongjiu No.12 at the heading stage were significantly higher than at the milking and mature stage. CP and P contents in stems of A. sativa cv.No.4632 at the heading stage were significantly higher than at the milking and mature stage. EE (ether extract) contents in seeds of A. sativa cv.Bayan No.3 at the milking (4.95%) and mature stage (5.48%) were significantly higher than at the heading stage (2.36%). Whole-plant water-soluble sugar contents at the milking (26.80%) and mature stage (24.11%) were significantly higher than at the heading stage (12.14%). water-soluble sugar content in stems of A. sativa cv.Qingyongjiu No. 87-6-21 and caloric values in seeds and whole-plant of No.4632 at the milking stage were significantly higher than at the heading and mature stage. CP contents in stems and seeds of No.4617 and No.4632 at the heading stage were higher than in the other varieties, water-soluble sugar contents in seeds, leaves, and whole-plant of No. 87-6-21 at the heading stage were higher than in the other three varieties. EE contents in stems and leaves of Qingyongjiu No.12, seeds of Bayan No.3 and whole-plant of No.4632 at the milking stage were higher than in the other varieties. CF contents in leaves, and stems of Bayan No.3, seeds and whole-plant of Qingyongjiu No.12 at the mature stage were the highest; NDF (neutral detergent fiber) contents in stems of No.4632, seeds of Qingyongjiu No. 87-6-21, leaves, and whole-plant of No.4617 were higher than in the other varieties, ADF (acid detergent fiber) contents in stems and leaves of Qingyongjiu No. 87-6-21, seeds of No.4632 and whole-plant of No.4617 were higher in than the other varieties.

Cultivar differences and classification of responses to nitrogen of Fe, Mn, Cu and Zn contents of triticale plant

KUANG Yi, LI Ting-xuan,YU Hai-ying

2011, 20(4):  82-89. 

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To assess cultivar differences in response to nitrogen of Fe, Mn, Cu and Zn contents and their types in triticale (Triticosecale) plants at the optimum cutting stage-heading stage, a potted plant experiment was carried out using two N levels (low and normal N) using 31 triticale cultivars from different origins. 1) Under normal nitrogen supply, Fe, Mn, Cu, Zn contents in triticale plants were significantly higher than those in plants with a low nitrogen supply. There were cultivar variations in Fe, Mn, Cu, Zn contents. Coefficients of variation were 14.16%-32.75%. In addition to the cultivar and N levels, there was a cultivar×N interaction of micronutrient contents. 2) There were also variations in the response of Fe, Mn, Cu, Zn contents in triticale plants. Based on the range and coefficients of variation of Fe, Mn, Cu, Zn contents in triticale under two N levels, the response of Fe, Mn, Cu, Zn contents in triticale plants to N levels could be classified into three types: insensitive, intermediate, and sensitive types.3) Correlation analysis showed that Fe content was not significantly correlated with shoot biomass in triticale but there were significant or highly significant correlations (coefficients of 0.36, 0.43 and 0.44, respectively) between Mn, Cu, Zn contents and shoot biomass in triticale plants. So, the cultivar×environment interaction can be manipulated to reach higher productivity and enrichment of micronutrient in triticale planting and breeding.

Effect of phosphate on carbohydrate accumulation of silage Zea mays in different harvest periods

LI Hong-ying, YAN Shi, SUN Tao, LI Ji-kai, CUI Guo-wen

2011, 20(4):  90-97. 

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The concentration of water soluble carbohydrates (WSC) is a main determinant of ensiling potential of forages and aerobic stability of silages. Trials were carried out to define the effect of different phosphate applications on carbohydrate accumulation of Zea mays silage in different harvest periods. The experiment used Dongqing No.1 to study the effects of four phosphate fertilizer (P₂O₅) levels (0, 50, 100, 150 kg/ha) on carbohydrate content of the silage during the initial milk stage (21 August), milk stage metaphase (28 August), milk stage telophase (4 September), initial dough stage (10 September), dough stage metaphase(15 September) and late dough stage metaphase (20 September). From the initial milk stage to dough stage metaphase, fructose and total soluble sugar contents were in the sequence P2>P3>P1>P0, while starch content was P2>P1>P3>P0. The various phosphate levels were significantly different (P<0.05); Sucrose content increased significantly with higher phosphate levels, but was not significantly different between P2 and P3 which were significantly higher than the other levels (P<0.05). In different phosphate levels, NDF and ADF contents of P0 were the highest while P2 was the lowest and was significantly lower than those in the other treatments (P<0.05). Consequently phosphate significantly enhances fructose, sucrose, total soluble sugar and starch contents, but reduces NDF and ADF contents in Z. mays silage at different harvest periods (P<0.05). In summary, applying phosphate (P₂O₅) 100 kg/ha and harvesting at the initial dough stage resulted in the highest content of total soluble sugars and the lowest content of NDF and ADF of Z. mays silage and are the most suitable cultivation practices for Dongqing No.1.

Seasonal changes of freezing tolerance and its relationship to the contents of carbohydrates, proline, and soluble protein of Zoysia

WANG Dan, XUAN Ji-ping, GUO Hai-lin, LIU Jian-xiu

2011, 20(4):  98-107. 

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To clarify the changes of carbohydrates, proline, soluble protein contents and their relationships to freezing tolerance of Zoysia japonica ‘Lanyin No.3’, the relationship of carbohydrate (total soluble sugars, sucrose, glucose, starch), proline and soluble protein concentrations with LT₅₀(the lethal temperature killing 50% of the plants) of rhizomes were studied at monthy intervals from October, 2008 to May, 2009 under natural cold conditions. The contents of carbohydrates, proline, soluble protein and LT₅₀ showed a clear seasonal trend in rhizomes of Z. japonica ‘Lanyin No.3’ and they increased or decreased sharply as temperatures dropped in overwintering and decreased or increased gradually along with the rise in temperature in spring. Correlation analysis revealed that the freezing tolerance of rhizomes of Z. japonica ‘Lanyin No.3’ positively correlated with the contents of total soluble sugars, glucose and the ratio of the soluble sugars to starch but had no positive correlation with the contents of sucrose, starch, and proline.

Photosynthetic responses of four dominant species to environmental gradient along the oasis-desert ecotone of Minqin, China

TIAN Xin-min, ZHAO Chang-ming, DENG Jian-ming, ZHANG Xiao-wei, CHEN Tuo, REN Jia-wen, WANG Gen-xuan

2011, 20(4):  108-115. 

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The vegetation of the oasis-desert ecotone plays an important role in the desertification control, therefore the evaluation of the dominant plant growth and health is very important. The photosynthetic characteristics of four dominant plant species (i.e. Nitraria tangutorum, Phragmites communis, Haloxylon ammodendron and Calligonum mongolicum) in four different distributing sites along the oasis-desert ecotone (i.e. section 1, section 2, section 3, section 4 from the oasis to the desert) were investigated in this study. The water content, chlorophyll content of four species decreased gradually while the carotenoids content increased gradually along the oasis-desert ecotone, showed that four plant species suffered from the different extent of drought stress. The photosynthetic capacity of four plant species decreased gradually along the gradient of the ecotone, while the decreasing extent was different [the decrease of N. tangutorum was the least, H. ammodendron and P. communis were biggist, while the photosynthetic capacity of C. mongolicum was higher in the section 1 (the margin of oasis) and section 3]. The variational trend of stomatal conductance (Gs) in the four plant species was the same as the variational trend of photosynthetic capacity, but there were different with the trend of transpiration rate (E) and water use efficiency (WUE). The WUE of N. tangutorum and P. communis were highest in the section 2, C. mongolicum was highest in the section 3, while the WUE of H. ammodendron decreased gradually along the ecotone. In addition, the variational trend of chlorophyll fluorescence parameters (F_v/F_m and F_o) of four plant species indicated that the H. ammodendron occurred the long-term photoinhibition and photodamage along the ecotone, while the N. tangutorum was not influence, and that the C. mongolicum and P. communis only suffered from serious stress in the section 4 (i.e. the margin of desert). In conclusion, all our results suggested that the N. tangutorum adapt to the drought conditions of oasis-desert ecotone more than C. mongolicum and P. communis, while the adaptive capacity of H. ammodendron was the worst in the four plant species.

A study on photosynthetic characteristics of different Salvia miltiorrhiza varieties

ZHONG Guo-cheng, ZHANG Li-wen, ZHANG Li, YANG Rui-wu, DING Chun-bang

2011, 20(4):  116-122. 

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To provide basic data for planting S. miltiorrhiza cv. silcestris and S. miltiorrhiza cv. sativa, their photosynthetic characteristics were studied. A LI-6400XT portable photosynthesis system was used to measure diurnal dynamics of the photosynthetic characteristics and light-response curve of photosynthesis. The light compensation point and light saturation point of S. miltiorrhiza cv. sativa were lower than those of S. miltiorrhiza cv. silcestris. The apparent quantum efficiencies were higher than 0.06, which showed that they had a strong utilization efficiency in weak light. Diurnal course curves of their net photosynthetic rates had two peaks, one occurred at 11:30 and the other at 14:30. Their “midday depression” occurred at 13:00. The “midday depression” of S. miltiorrhiza cv. silcestris was due to stomatal limitation while that of S. miltiorrhiza cv. sativa was not. Diurnal course curves of their stomatal conductance and transpiration rate had a single peak. The “midday depression” of S. miltiorrhiza cv. sativa was deduced to be due to localized water stress in leaves when the transpiration rate was high at midday. To ease “midday depression” and increase production of S. miltiorrhiza cv. sativa, some tall crops should be intercropped.

Physiological & biochemical responses of different leaves of Ophiopogon bodinieri to soil lead stress

LIU Bi-ying, PAN Yuan-zhi, ZHAO Yang-di

2011, 20(4):  123-128. 

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Ophiopogon bodinieri is an important turfgrass and ornamental cover plants which is widely used in urban garden construction in southern China. To understand the physiological & biochemical responses of different leaves of O. bodinieri to increasing Pb contamination, the effects of different soil Pb concentrations on the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and on the concentrations of free proline (Pro) and malondialdehyde (MDA) in different leaves were studied in a pot experiment with different Pb treatments. The activities of SOD, POD and CAT and the concentrations of Pro and MDA in fresh leaf (FL), mature leaf (ML), and old leaf (OL) of O. bodinieri were measured after Pb-exposure for 7 days. The activities of SOD, POD, and CAT increased at lower Pb concentrations, but decreased at higher ones, depending on the leaves and enzymes. Meanwhile, Pro and MDA concentrations in FL, ML and OL increased with increased soil Pb. The responses of different leaves of O. bodinieri to soil Pb stress differed. FL had higher activities of the antioxidative enzymes SOD, POD and CAT in comparison with the OL under the levels of soil Pb contamination tested, while the OL had higher concentrations of osmotic substances (Pro and MDA) in comparison with the FL and ML. O. bodinieri could adapt to a certain concentration range of soil Pb stress, and the response of fresh O. bodinieri leaves to soil Pb stress was more sensitive than that of old O. bodinieri leaves. The tolerance of old O. bodinieri leaves to soil Pb stress was stronger than those of fresh and mature leaves.

Effect of salt stress on ion absorption and distribution of two Lycium seedlings

WANG Long-qiang, MI Yong-wei, LIN Hai-ming

2011, 20(4):  129-136. 

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Na⁺, K⁺, Ca²⁺, Mg²⁺, Si⁴⁺ and Cl^- absorption and distribution in different organs of two Lycium seedlings(Lycium ruthenicum and L. barbarum) were studied under NaCl stress. There were higher Na⁺ and Cl^- relative contents of two seedlings than those of contrast, and its content became gradually higher with salt concentration increasing. Among different organs, accumulation of Na⁺ and Cl^- were the most highest in leaves tissue. On the contrary, K⁺, Ca²⁺, Mg²⁺ and Si⁴⁺ contents of seedlings under different salt tolerance reduced or did not vary compared with contrast. At the same time, the K⁺/Na⁺, Ca²⁺/Na⁺, Mg²⁺/Na⁺ and Si⁴⁺/Na⁺ ratios in leaves, stems and roots decreased gradually with salt concentration increasing under NaCl stress. The K⁺/Na⁺, Ca²⁺/Na⁺, Mg²⁺/Na⁺ and Si⁴⁺/Na⁺ ratios in L. ruthenicum under salt stress were markedly higher than those in L. barbarum, and the descendant degree of these ratios of L. ruthenicum were enormously lower than those of L. barbarum especially in higher salt concentration, which showed that L. ruthenicum had stronger ability than L. barbarum in salt tolerance.

A study on the major components and feeding value of Wuhe Glycine soja seed

LI Meng-liang, ZHENG Lin

2011, 20(4):  137-142. 

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The nutritional components and feeding value of Wuhe wild Glycine soja were studied through a field experiment and analysis test. The nutritional value of Wuhe wild G. soja is rich; The contents of protein, fat, crude fiber, total sugar, calcium, magnesium, total falconoid, total free amino acids were 38.92%, 16.94%, 4.1%, 10.14%, 0.357%, 0.059%, 0.13%, 960.2 mg/100 g crude protein, Zn and Cu contents were 37.3 mg/kg, 41.4 mg/kg, respectively. Protein and fat contents of Wuhe wild G. soja were close to that of common soybean. Among 13 fatty acids, contents of linoleic acid and oleic acid were quite high, and close to that of soybean and the linolenic acid content was higher than that of soybean. Of 17 amino acids, tyrosine, aspartic and glutamic acid contents were plentiful, but phenylalanine, methionine and tryptophan were the limiting amino acid components. Wuhe wild G. soja had good feeding value, and it can be developed as good-quality protein feed.

Structure foundation and ecological adaptability of Alternathera philoxeroides in heterogeneous habitats

WANG Gui-qin, GAO Rui-ru, WANG Yu-liang, CHAI Rui-juan

2011, 20(4):  143-152. 

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The morphogenesis and anatomical changes of Alternathera philoxeroides in different habitats (xeric and aquatic environments), were chosen as characteristics to appraise this weed under heterogeneous habitats. There were significant differences between the vegetative organs from two ecotype due to adaptation to heterogeneous ecotypes. The distribution and quantity of stomata between the two leaves showed a notable distinction; leaves of the xeric form had long epidermal hairs on both upper and lower epidermis, while the aquatic form had none on either. There were also significant differences as to type, quantity and proportion of conducting tissue in stems from different habitats and different ecobiomorphisms. The perennial roots from the xeric’s stolon and rhizome had many adventitious buds which contained a high content of stored substances, and had the material and structural basis to be independent diasporas. In contrast, the aquatic only had numerous fibrous roots to meet absorption needs. The pollens of A. philoxeroides had a high abortion percentage (approximately 80%), which may be one reason for its low seed setting rate, but how it achieves invasion over long distances with such a low sexual reproduction rate deserves to be discussed, because of its significance in weed control.

Pollen abortion of alfalfa in different ecological regions in Xinjiang and cytological observations of factors affecting pollen abortion

HE Shuang, ZHANG Ai-qin, XIA Rong, LI Xiao-ye, ZHU Hong-juan

2011, 20(4):  153-158. 

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Research on pollen abortion of alfalfa (Medicago) and cytological observation of factors affecting it was carried out for two years in four different ecological regions of alfalfa including eight observation points in Xinjiang. 1) The pollen abortion percentages differed significantly between the different ecological regions and between different alfalfa plots in the same region. In 2008, the pollen abortion percentage of different alfalfa plots were: Tacheng (20.05±5.33)%,(23.41±3.76)%, (29.80±5.45)%, (P<0.05); Yili(28.34±3.19)%; Hutubi(15.57±2.18)%, (31.47±4.59)%, (P<0.05);Hetian(20.79±2.89)%, (26.51±4.74)%, (P<0.05). 2) The alfalfa pollen abortion percentages were significantly different between different years at the same observation point. In 2007, the alfalfa pollen abortion percentage of M. varia cv. Xinmu No.1 and M. sativa cv. Xinjiang Daye were (37.96±2.10)% and (38.70±2.40)% respectively in the Hutubi alfalfa seed base, and in 2008 the alfalfa pollen abortion percentages were (15.57±2.18)% and (31.47±4.59)%, (P<0.01). 3) At the group level, pollen abortion percentages did not show significant differences at different stages of anthesis, but did have a significant differences between single flowers distributed on the same alfalfa plant, but with no obvious location or time effect. 4) From the cytological characteristics of pollen development, there was no significant limiting factor affecting pollen abortion during pollen development. The fluctuatation of the tapetum degradation period was influenced by environmental factors leading to differences of pollen abortion of the same alfalfa variety between different ecologic region and years.

Optimization of SRAP-PCR system and its application in genetic diversity analysis of Stylosanthes

ZHANG Wei-li, LIU Feng-min, LIU Ai

2011, 20(4):  159-168. 

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Two different genotypes of Stylosanthes germplasm, S. guianensis cv. Reyan No.2 and S. guianensis cv. Reyan No.13 were used as material for studying the effects of concentrations of Mg²⁺, dNTPs, DNA polymerase, primers and DNA template on the SRAP-PCR reactions and optimizing the establishment of SRAP molecular marker system in Stylosanthes. The optimum system was established as follows: template DNA 40 ng, Mg²⁺ 2.5 mmol/L, dNTPs 0.2 mmol/L, polymerase 1 U, primer 0.3 μmol/L, the total reaction volume was 25 μL. The genetic diversity and relationships of nine Stylosanthes germplasms were analyzed by using this optimum system. Forty-eight primers were studied for an analysis of genetic diversity by SRAP in Stylosanthes germplasms. Fourteen effective primers selected from 48 primers combination were used for SRAP-PCR, and 150 of the 154 DNA fragments amplified, showed polymorphisms. The average binds from each primer was 11.0 and the average percentage of polymorphic bands was 97.36%. The Nei’s genetic similarity coefficient of the tested accessions ranged from 0.386 to 0.882 by software NTSYSpc 2.1 based on SRAP results, and the average Nei’s coefficient was 0.631, average the genetic distance(GD) was 0.369. Based on the presence of bands, nine Stylosanthes germplasm were classified into there major groups by UPGMA cluster analysis, group Ⅰ, group Ⅱ and group Ⅲ. Group Ⅰ included S. hamata cv. Verano, and group Ⅱ included S. scabra cv. Seca. Group Ⅲ included S. guianensis cv. Reyan No.5, S. guianensis cv. Reyan No.10, S. guianensis cv. Reyan No.13, S. guianensis cv. White cook, S. guianensis cv. Reyan No.2, S. guianensis cv. Graham and S. guianensis tardio CIAT1283. This research should provide a scientific basis at the molecular level for further study and the application of nine Stylosanthes germplasms. The most of the varieties with relative relationship in their pedigrees and similar biological characteristics were clustered into the same group.

Cloning and differential expression analysis of S-adenosylmethionine decarboxylase gene FaSAMDC in tall fescue

WANG Xiao-li, LIU Xiao-xia, WANG Shu-yin, YANG Yi-cheng, WU Jia-hai

2011, 20(4):  169-179. 

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We screened 5′ end sequence of S-adenosylmethionine decarboxylase gene when identified 5′ end sequence of phytochrome C gene from tall fescue. The primers were designed and amplified 3′ end sequence based on the 5′ end sequence of S-adenosylmethionine decarboxylase gene, 5′ end sequence and 3′ end sequence were jointed, a SAMDC of cDNA from tall fescue has been identified, and designated as FaSAMDC(GenBank Accsssion: HQ606139). Theoretical basis of different photoperiods regulated FaSAMDC expression was provided through a study of FaSAMDC differentially expressed during 24 hours in long-days and short-day using real-time fluorescence quantitative PCR. The cDNA of FaSAMDC is 1 964 bp in length and contains three open reading frames, tiny upstream ORF (226-234 bp), small upstream ORF (234-380 bp), main ORF (555-1 742 bp) respectively. Main ORF encodes a protein of 395 amino acids. Domain analysis reveals that proteins encoded by FaSAMDC genes contain two conserved domains: Proenzyme splice site domains and involving SAMDC protein rapid degradation PEST domain. FaSAMDC showed a close genetic relationship with the known SAMDC of monocotyledonous plants. Three expression peaks was detected in both long days and short days condition. The level of FaSAMDC expression peak under long days was significantly higher than that under short days. However, the peak of FaSAMDC transcription level under short days condition was earlier several hours than that of long days condition. This indicates that FaSAMDC gene transcripted with a circadian rhythm and was regulated by photoperiod.

A rudimentary study of the acid fibroblast growth factor’s plant expression vector construction and transformation into Medicago sativa

JIANG Shi-cui, WANG Yi, SUN Chun-yu, WANG Yan-fang, LI Xiao-kun, ZHANG Mei-ping

2011, 20(4):  180-186. 

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After optimization of the aFGF gene for the chosen plant, the codon, the signal peptide, six-histone tag and zymoplasm cutting factor were added to the modified TΩAB plasmid, which was named TΩAB-aF after the recombination of the aFGF gene and enhancer sequence, promoter, Ω-sequence and ployA tailing sequence double digests. The binary expression vector pBI121-TΩAB-aF was constructed using TΩAB-aF and pBI121. By triparental mating the vector pBI121-TΩAB-aF was transformed into LBA4404. Medicago sativa was transformed using Agrobacterium tumefaciens, followed by selective screening and PCR, RT-PCR and Western Blot analysis. The aFGF was expressed in M. sativa.

Cloning and expression analysis of aldehyde dehydrogenase gene LcALDH from Leymus chinensis

LI Xin-ling, WU Shu-ju, WANG Quan-wei

2011, 20(4):  187-193. 

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In this research, cDNA(GenBank No. EF492045) of aldehyde dehydrogenase gene LcALDH was isolated from Leymus chinensis by RACE technology.The nucleotide sequence of LcALDH cDNA is 1 712 bp containing an open reading frame of 1 503 bp encoding 500 amino acids, with a 5′untranslated region of 66 bp and a 3′untranslated region of 144 bp. The amino acid sequence contains absolutely conservative glutamic acid and cysteine residues active sites of aldehyde dehydrogenase family. The analysis of LcALDH gene expression under different stress condition showed that LcALDH expression was positively regulated by low-temperature, drought, high salt and ABA. The research results will lay the foundation for both the further exploration of the stress resistant mechanism of L. chinensis from molecular level, and the utilization of plant gene.

Analysis of chromosome karyotypes on three germplasm of Elytrigia repens

ZHANG Xiao-yan, MAO Pei-chun, MENG Lin, GAO Hong-wen, ZHANG De-gang

2011, 20(4):  194-201. 

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The chromosome karyotypes of three germplasm of Elytrigia repens were studied using the root tip squash method in order to provide the important scientific basis for the researches of cytological characteristics and evolutionary tendency. The results showed that the chromosome type of ER044 growing in Leningred of Russia was K(2n)=6X=42=2M+32m+8sm, the composition of relative length chromosomes was 4L+14M₂+20M₁+4S.The chromosome type of ER058 growing in Kabul of Afghanistan was K(2n)=6X=42=30m+12sm(2sat), the composition of relative length chromosomes was 2L+20M₂+16M₁+4S. The chromosome type of ER132 growing in Xinjiang, China was K(2n)=6X=42=32m+8sm(4sat)+2st, the composition of relative length chromosomes was 4L+16M₂+16M₁+6S. The chromosome karyotypes of three germplasm were belonged to “2B” types.

A study on quality of mixed silage of alfalfa and corn

WANG Lin, SUN Qi-zhong, ZHANG Hui-jie

2011, 20(4):  202-209. 

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To assess the best ratio for mixed silage of corn and alfalfa, they were mixed and ensiled in different proportions (0∶10,3∶7,5∶5,7∶3,10∶0 respectively) and after 30 days, the nutrition and fermentation quality of all treatments were determined and analyzed. 1) Compared with alfalfa silage, all three treatment improved fermentation quality and attained the goal of excellent silage. 2) CP (crude protein) and Ash (crude ash) contents of the 3∶7 treatment were significantly higher than corn but lower than alfalfa silage (P<0.05), NDF (neutral detergent fiber) and ADF (acid detergent fiber) contents were significantly lower than corn but higher than alfalfa silage (P<0.05). 3) pH values of the 5∶3 and 7∶3 treatments were significantly lower than that of alfalfa silage(P<0.05). Lactic acid contents of all three mixed treatments reached more than 60%, but the contents of acetic acid and propionic acid reduced, and produced little butyric acid compared with alfalfa silage. 4) The number of lactic acid bacteria on alfalfa silage increased to 10⁸ cfu/g FM after ensilling, while that on corn silage stayed the same before and after fermentation. Escherichia coli of mixed silage decreased significantly after ensilling. The mixed treatment modulated silage of high quality more easily, and the nutrition and fermentation quality of mixed silages were between corn and alfalfa silage. The fermentation quality of the 7∶3 treatment was the best.

Effects of alfalfa saponins on the lipid metabolism, antioxidation and immunity of weaned piglets

WANG Cheng-zhang, WANG Yan-hua, SHI Ying-hua, YAN Xue-bing, HE Yun, FAN Wen-na

2011, 20(4):  210-218. 

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To evaluate the effects of alfalfa (Medicago sativa) saponins on lipid metabolism, antioxidation and immunity of weaned piglets, the piglets were weaned at 3 weeks when the average body weight was 9.2 kg. They were divided into four treatments, three replicates per treatment and four piglets per replicate in a complete random single factorial design. The levels of alfalfa saponins were 0% (control group), 0.25% (groupⅠ), 0.50% (group Ⅱ), and 1.00% (group Ⅲ). 1) Triglycercide (TG) contents of the three trial groups of blood serum were significantly lower than that of the control group, and that of group Ⅲ was very significantly lower than that of the control group (P<0.01), but alfalfa saponins had no effects on the liver TG content; The total cholesterol (T-CHO) content of the trial groups blood serum were very significantly lower than that of the control group (P<0.01), but high density lipoprotein cholesterine (HDL-CHO) content of blood serum was significantly higher than that of the control group while low density lipoprotein cholesterine (LDL-CHO) content was the opposite of HDL-CHO. When the piglets were fed with alfalfa saponins, the number of TG of liver was significantly reduced (P<0.05), that of HDL-CHO increased, but cholesterol content of the eye muscle decreased. 2) As the alfalfa saponins levels increased, glutathione peroxidase(GSH-Px) activity increased, and those of group Ⅱ, Ⅲ were significantly higher than that of the control group, but malonaldehyde (MDA) content was the opposite (P>0.05). 3) Contents of total protein (TP) and albumin (ALB) of blood serum were improved when the piglets were fed with alfalfa saponins, however, there were no significant differences among trial groups and the control group; IgG contents of trial groups were very significantly (P<0.01) higher than that of the control group, indicating that alfalfa saponins can improve the immunity of weaned piglets. The suitable alfalfa saponins contents were useful for reducing cholesterol content of blood serum, liver and eye muscle, adjusting the lipid metabolism, and improving the oxidation resistance and immune function.

Effects of fresh alfalfa levels and alfalfa meal in the diet on the production performance of sows

PENG Bao-an, GAO Yong-ge, WANG Cheng-zhang, WANG Yan-hua, ZHANG Xiao-xia, HAN Ming-peng

2011, 20(4):  219-228. 

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To evaluate the effects of replacing concentrate with different levels of fresh alfalfa (Medicago sativa) or alfalfa meal on the production performance of sows a single-factor and randomized block design was used. Thirty Large White×Landrace sows, with similar mating date, birth order, superior fetal litter size, and body condition, were divided into six groups with five pigs per group, one pig for each duplicate. The pregnant swine of the control group was fed the basal diet (0% alfalfa), while those of test groupsⅠ, Ⅱ, Ⅲ and Ⅳ were replaced with 10%, 20%, 30%, 40% fresh alfalfa (by dry matter %), respectively, and that of test group Ⅴ was replaced with 20% alfalfa meal. 1) Compared with the control group, the digestibility of all test groups, including CP (crude protein), Ash (crude ash), NDF (neutral detergent fiber), ADF (acid detergent fiber), Ca and P were improved, and the digestibility of group Ⅲ was significantly higher than that of the control group (P<0.01); As the fresh alfalfa level was increased, the apparent digestibility of crude fat decreased but there was no significant difference between the alfalfa meal group and the control group. 2) As the fresh alfalfa level increased, the weight gain of breeding sows and the amount of backfat increased at first but then decreased, while the amount of backfat during pregnancy and backfat reduction during lactation decreased; Compared with the control group, the feed intakes of all test groups increased, and that of group Ⅲ was the biggest, and was significantly (P<0.01) greater than that of control group; Using fresh alfalfa and alfalfa meal, the interval of weaning to estrus was shortened, but there were no significant differences (P>0.05) between the groups. 3) Fresh alfalfa had a positive influence on the total newborn piglets, newborn live piglets, weaning piglets, weight of weaning litter and daily weight gain of weaning litters; The weights of weaning piglets of the fresh alfalfa groups (except group Ⅲ) were similar to the control group, but the alfalfa meal group of group Ⅴ was significantly higher (P<0.05) and the weight of weaning piglets and daily gain of group Ⅴ were significantly higher (P＜0.01) than those of the control and the other groups. In conclusion, replacing concentrate with 30% fresh alfalfa gave the best value of production performance and economic benefits in the pregnant swine diet.

A study on contact toxicity of extracts from Polygonum orientale against 13 species of agricultural pests

HU Guan-fang, LIU Min-yan, SHEN Hui-min, ZHANG Xin-rui, LI Yu-qi, NIU Shu-jun

2011, 20(4):  229-235. 

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Contact toxicity of extracts from Polygonum orientale against agricultural pests have seldom been researched. A study on contact toxicity of the extracts can provide a theoretical basis for formulating new types of botanical insecticide. Contact toxicity of the extracts against pests was carried out by the immersion method. Ethyl acetate extract from seeds of P. orientale had very strong contact toxicity against 4^th or 5^th instar larvae of Mythimna separate, Pieris rapae, Helicoverpa armigera, Mamestra brassicae, Spodoptera exigua and Agrotis ypsilon. Percentages of corrected mortality were between 87.5% and 100% when the concentration of the fraction was 16.80 g/L. The fraction also had very strong contact toxicity against 3^rd instar larvae of Plutella xylostella, with a corrected mortality of 92.85% when the concentration of the fraction was 21.00 g/L. The ethyl acetate fraction from stems of P. orientale collected in fall had very strong contact toxicity against 4^th instar larvae of P. rapae or 5^th instar larvae of M. separate with corrected mortalities of 100% or 59.20% (33.60 g/L). Petroleum ether extract from stems of P. orientale in blossom had stronger contact toxicity against Aphis gossypii, with corrected mortality of 51.65% (0.27 g/L). Petroleum ether and methanol extracts from flowers of P. orientale in blossom had very strong contact toxicity against Tetranychus cinnabarinus, with corrected mortality of 100% (0.13 and 1.15 g/L).

Changes of Fusarium in rhizosphere soil under potato continuous cropping systems in arid-irrigated area of Gansu Province

NIU Xiu-qun, LI Jin-hua, ZHANG Jun-lian, SHEN Bao-yun, CHAI Zhao-xiang, WANG Di

2011, 20(4):  236-243. 

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For a thorough understanding of the relationships between the distribution of Fusarium in rhizosphere soil and potato continuous cropping systems, the changes of Fusarium in rhizosphere soil under potato continuous cropping and rotation cropping were studied by way of root debris separation using the cultivar Atlantic. There were 8 species of Fusarium from rhizosphere soils of different rotations. F. proliferatum was the dominant species of corn-potato rotation systems with a separation frequency up to 23.34%, but in rhizosphere soils of potato continuously cropped for 1-3 years, F. solani was the dominant species with separation frequencies up to 30.78%, 37.70% and 45.48%. With long term continuous cropping of potato, the total amount of Fusarium tended to increase but there were changes in the different Fusarium species. The amounts of F. solani and F. oxysporum increased while the amounts of F. culmorum and F. proliferatum decreased, and the amount of F. equesiti did not changed.

Isolation and identification of four new Erwinia carotovora subsp. carotovora strains

ZHAO Ling,CHAI Zhao-xiang,LI Jin-hua,WANG Di

2011, 20(4):  244-251. 

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Rhizosphere soils of potato (Solanum tuberosum) were sampled via a chess-board pattern from fields of potato grown for one year, continuously for 2 years, 3 years and 4 years at 4 growing stages (before planting, squaring stage, maturity stage and harvest stage). The soils were isolated on CVP medium via the dilution method for soft rot Erwinia and 42 strains were obtained. During observations of morphology and tests of their physiological and biochemical characteristics, it was found that 4 of the 42 strains shared the same characteristics but differed from the other strains. The 4 strains were GAUP-b410, GAUP-b492, GAUP-b416 and GAUP-d34. The pathogenicity tests indicated that these 4 strains were artificially pathogenetic to cut potato pieces. GAUP-b410 and GAUP-b492 were taken at random for analysis of 16S rDNA sequence, which showed 99% sequence identity with 18 E. carotovora subsp.carotovora strains from Chinese cabbage in China after aligning data in GenBank. Microsoft DNAStar was used to draw the phylogenetic tree of strain GAUP-b410 and GAUP-b492. The tree showed that strain GAUP-b410 was in the same cluster as the 18 Chinese strains, while strain GAUP-b492 was in the same cluster as the 16 of 18 Chinese strains. Therefore, based on the physiological and biochemical characteristics of the 4 strains and the result of 16S rDNA sequence analysis of the 2 strains, the 4 strains were identified as the E. carotovora subsp.carotovora, which were 4 new E. carotovora subsp.carotovora strains.

Research on validating MODIS/LAI product in a typical semi-arid steppe of Xilinhot in Northern China

WANG Yuan-yuan, WANG Meng, LI Gui-cai, WANG Jun-bang, YANG Zhong-dong, RONG Zhi-guo

2011, 20(4):  252-260. 

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MODIS/LAI product in a typical semi-arid steppe of Xilinhot in Northern China was validated based on three comprehensive field surveys which were carried out during July-August 2008 in the study area. LAI was measured in 25 m×25 m plots by a destructive harvest method of 80 intensive plots and 20 scattered plots. Three TM/ETM+ images acquired during the field survey periods were collected and processed. The validation work covered two parts: Time series analysis and spatial pattern analysis. In time series analysis, MODIS/LAI track in the intensive sampling region extracted from DOY169 to DOY241 were compared with ground measured values. In spatial pattern analysis, LAI map with 30 m spatial resolution were first derived by building a regression line between LAI and TM band 5 (1.6 μm), and then aggregated to 1 km spatial resolution based on MODIS grids. Results indicated that in the temporal domain MODIS/LAI product can correctly reflect grass growth trends; In the spatial domain it showed a similar pattern with TM/LAI (1 km). Using the TM/LAI as reference, the relative RMSE of MODIS/LAI was about 24% and a positive bias (10.8%) existed, suggesting slight over-estimation. Error distribution analysis revealed that the MODIS/LAI product was less accurate in regions with lower LAI values, probably due to soil contamination. Moreover, the relative RMSE of the MODIS/LAI product was higher at the beginning of July and the end of August when the heterogeneity of grass cover increased as a result of human activities.

Application of cell engineering in improving Miscanthus as a dedicated bioenergy crop

LIU Ming-xi, JIANG Jian-xiong, YI Zi-li

2011, 20(4):  261-269. 

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Biomass energy is an important renewable energy source and Miscanthus is considered as one of the most promising biomass energy crops. The research has been funded in the European Union and America for Miscanthus, especially the triploid species Miscanthus×Giganteus. The application of cell engineering in improving Miscanthus as a dedicated bioenergy crop is summarized as follows: 1) Studies of in vitro regeneration systems for Miscanthus, focusing on callus induction and differentiation or shoot proliferation, in which the main factors influencing regeneration efficiency were evaluated, including hormones, explants, supplementary additions, medium compositions, different carbon sources and their sterilization methods; 2) Studies of chromosome ploidy manipulation for Miscanthus, mostly for in vitro chromosome doubling of Miscanthus but one for haploid breeding. At the end of this paper the developing trends of cell engineering for the energy crop Miscanthus are briefly discussed.

Research advances in genetic regulation of gametophyte development in Medicago sativa

LIU Zhi-peng, ZHANG Ji-yu, WANG Yan-rong

2011, 20(4):  270-278. 

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The actual seed yields of Medicago sativa are far less than the potential yield. The key reasons are ovule abortion and abnormal development of the gametophyte. Therefore, there is an important relationship between gametogenesis and seed yield of M. sativa. Stamens and carpels of M. sativa belong to the third and fourth wheel of the flower organ, respectively. The normal male and female gametophytes that develop from these two tissues are essential to sexual reproduction of M. sativa. Based on the gametophyte genetic regulation of model plants such as Arabidopsis thaliana, Oryza sativa, and Zea mays, and combined closely with the gametophyte development of the leguminosae model plant Medicago truncatula, this review discusses in detail the recent advances in male and female gametogenesis of M. sativa with a focus on the genetic regulation, molecular biology, and cytology of these processes.

Grasslands eco-environment and stockbreeding development in the karst areas of Guizhou province

GAO Jian-fei, SU Xiao-liang, XIONG Kang-ning, ZHOU Wei

2011, 20(4):  279-286. 

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In the karst areas of Guizhou province, utilizing the data of Guizhou land-use and rocky desertification RS investigation, and GIS spatial analysis, 24 686.74 km² grasslands (67.57% of the whole provincial grasslands) were selected in the karst areas of Guizhou province. Of these areas, 39.77% was rocky and desertified. In last 20 years, through introduction of forage grass, domestic animal species and advanced techniques and accompanied by experimention and advocacy, we have collected a full range of experiences on modification of domestic animal species, planting and cultivation of pasture, stocking modification, rotations, and intercropping. There are various grassland resources in the karst area of Guizhou province with a good future for pasture and stock, but traditional extensive management is in domestic areas with fewer supporting facilities, and less scientific support so that the ability to face disaster, particularly serious atmosphere change is weak. The soil here is weak, with grassland degeneration. An active demand for technology such as good methods of grassland planting and cultivation, local species cultivation, animal husbandry industry technology and scientific support systems, and management maintainance for restoration of grassland ecological systems are necessary.

Genetic diversity and genetic variation of Ceratoides arborescens wild populations in Inner Mongolia

WANG Pu-chang, ZHAO Li-li, YI Jin, ZHANG Jin-hua

2011, 20(4):  287-292. 

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By using inter-simple sequence repeat (ISSR) markers technique, this paper studied the genetic diversity and variation of six wild populations of Ceratoides arborescens. The results showed that at species level the percentage of polymorphic bank (PPB) was 98.05%, Nei’s gene diversity (h) and Shannon’s index (I) were 0.298 4 and 0.455 7, respectively. According to PPB, h and I, estimated the trend line of the average genetic diversity within each population was similar, the order was PA>PB>PD>PC>PE>PF. There were more genetic variations within the population than among populations. The gene flow is 4.333 2 among populations, were greater than 1. The cluster analysis suggested that the six populations of C. arborescens could be divided into two groups, i.e. desert grassland group and typical grassland group. The habitat fragmentation was still not enough to cause the loss of specific gene, genetic drift occured very unlikely.

Effects of soil water stress on seedling growth and water use efficiency of two desert shrubs

FENG Yan, WANG Yan-rong, HU Xiao-wen

2011, 20(4):  293-298. 

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Seedling growth, water use efficiency and leaf carbon isotope composition (δ¹³C value) of Zygophyllum xanthoxylum and Caragana korshinskii were measured at different soil water stress levels in a pot experiment. The correlation between growth and water use efficiency was analyzed. 1) Severe water stress seriously decreased the total biomass, above ground biomass, total leaf area and leaf number of Z. xanthoxylum and C. korshinskii; 2) As water stress increased, water use efficiency and the δ¹³C value increased. Water use efficiency and the δ¹³C value had a significant (P<0.05) positive relationship; 3) Water use efficiency had a significant negative relationship with total leaf area, leaf number(P<0.01), and total biomass(P<0.05);4) The biomass and total leaf area of C. korshinskii were significantly smaller than those of Z. xanthoxylum, but the root/shoot ratio was bigger. C. korshinskii is sensitive to water stress and its biomass, leaf area and leaf number are considerably reduced by this stress;5) Under the same water stress gradient, water use efficiency of C. korshinskii is lower but the δ¹³C value is higher than those of Z. xanthoxylum.

Physiological responses of Agropyron cristatum under Na₂CO₃ and NaHCO₃ stress

GAO Wen-jun, XU Jing, XIE Kai-yun, DONG Kuan-hu

2011, 20(4):  299-304. 

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Seedlings of Agropyron cristatum were stressed with Na₂CO₃ and NaHCO₃ (0, 30, 60, 90, 120, or 150 mmol/L) in the greenhouse. Eight indices (biomass, root-shoot ratio, malondialdehyde (MDA) content, chlorophyl content, soluble sugar content, proline content, SOD activity and POD activity) were determined. As the stress increased in treatments, the content of MDA and soluble sugar also increased whereas the biomass, root-shoot ratio, and chlorophyl content increased initially and then decreased. The results showed that low concentrations of alkaline stress on A. cristatum had some role in promoting growth. Proline accumulated before soluble sugar and Na₂CO₃ stress was greater than NaHCO₃ stress.

Establishment of a gametocidal chromosome 2C specific SCAR marker

XU Guo-hui, GUO Chang-hong, YU Hong-tao, CHEN Jing, CONG Wen-wen, ENDO T R

2011, 20(4):  305-310. 

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A total of 40 decamer oligonucleotides were used as primers to perform random amplified polymorphic DNA (RAPD) analysis on common wheat CS (Chinese spring), CS-2C disomic addition line, Aegilops cylindrica. Of these primers, one could amplify a specific DNA fragment in CS-2C disomic addition line and A. cylindrica. The fragment OPF03₁₄₉₆ was cloned and sequenced; Sequence data searching in GenBank showed that this fragment was 92% homologous to a cloned cDNA sequence from Barley. Based on the sequence of OPF03₁₄₉₆, a pair of SCAR (sequence characterized amplified region) primer 2C-F₅₈₆, 2C-R₅₈₆ was designed. SCAR analyses were performed on CS, CS-2C disomic addition line, A. cylindrica, and Thinopyrum elongatum (2X) CS-7E disomic addition line. The amplification results of SCAR primer showed that the SCAR₅₈₆ marker appeared in the CS-2C disomic addition line and A. cylindrica but not in CS, T. elongatum (2X) CS-7E disomic addition line. Furthermore, SCAR analyses were also performed on F₁ and F₂ progenies between CS-2C and CS-7E disomic addition lines. PCR amplification results showed that the SCAR₅₈₆ marker was in all of the F₁ progenies between CS-2C and CS-7E and in some of the F₂ progenies. The SCAR₅₈₆ marker can be used for detecting the gametocidal chromosome 2C in common wheat backgrounds.

Genetic variation analysis of gliadin from wild germplasm of Psathyrostachys juncea

CHEN Shi-yong, MA Xiao, ZHANG Xin-quan, WU Xiao-long

2011, 20(4):  311-315. 

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Acid polyacrylamide gel electrophoresis (A-PAGE) was used to analyse the gliadin genetic variation among thirty-five wild accessions of Psathyrostachys juncea collected from Xinjiang in China, the Siberia region in Russia, and from Mongolia. 1) A total of 37 bands were obtained from the accessions and all were polymorphic; 2) The Dice genetic similarity coefficient of the tested materials ranged from 0-0.827 6, with a mean of 0.450 9. There was rich genetic polymorphism among the tested wild materials of P. juncea; 3) The 35 wild accessions can be divided into five groups and can be clustered with the same or similar eco-geographical origins. Results also showed some relationship between the patterns of gliadin bands and geographical distribution; 4) Genetic differentiations between and within groups were estimated by Shannon’s diversity index. The results showed H_t=0.579 6 and H_group=0.483 5, which indicated that 83.42% genetic variance existed within groups, and 16.58% genetic variance was between the groups. This might be related to the cross-pollinated breeding system of P. juncea. The results of the study will supply more information for germplasm resources, conservation and breeding of P. juncea.

Spatial-temporal dynamics simulation of grassland net primary productivity using a satellite data-driven CASA model in Gannan prefecture

WANG Ying, XIA Wen-tao, LIANG Tian-gang

2011, 20(4):  316-324. 

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Net primary productivity (NPP) and its responses to global change are one of the focuses of global change research. Based on GIS technology and remote sensing imagery, the grassland NPP and its spatial-temporal dynamics in Gannan prefecture during 2001 to 2008 were estimated with the Carnegie-Ames-Stanford Approach (CASA) model. Average annual NPP from 2001 to 2008 was 483.41 g C/(m²·a) in the study area. There was obvious seasonal change in the grasslands of Gannan, and the main growth period lasts from 177 to 240 days. There was a rising trend in the grassland NPP of the eight years. Between different grassland types, the trend of rising NPP on lowland meadow was the largest while that on marsh was smallest. Analysis of the temperature and precipitation of the eight years showed that the temporal variation of NPP was mainly influenced by changes of annual precipitation.