Table of Content

20 June 2011, Volume 20 Issue 3

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Spatial distribution pattern of soil nutrient contents in Jiuzhaigou Manaoke Gold Mine Valley, Sichuan, China

LI Wu-bin, HE Bing-hui, WANG Li, SHEN Jian-hong, HUANG Zhi-qing, ZHANG Xing-hua, WEN Ji-jian, DAI Wan-gui

2011, 20(3):  1-9. 

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Basic data for ecological restoration around gold mines was sought by comparing, the spatial distribution pattern of principal soil nutrient contents (including available N, P, K and organic carbon (SOC)) on the residue slope (including excavating slope and slag slope, etc.) with those in the original meadow/grassland which has the same habit of a south slope (at altitudes of 2 900 to 3 500 m) near the Jiuzhaigou Manaoke Gold Mine. Soil nutrient content of the residue slope did not differ significantly with altitude. The available nutrients were low and the averaged available N and K were far lower on the residue slope than those of the corresponding original grassland where the contents of soil available N, P and K decreased with increases in altitude and soil depth, and where the nutrients were lower at the slope-ridge than at the slope-valley. SOC in the original grassland initially decreased with increasing altitude, then increased, and finally decreased again. The correlations between contents of available N, P and K and SOC were significant in the original grassland. Environmental factors, including altitude, soil depth, ridge and valley slope, greatly influenced the distribution of soil nutrients and SOC as did soil disturbance.

A simulation study on the sustainable use of soil water in dry land for alfalfa-crop rotation systems in the semiarid region of southern Ningxia

WANG Xue-chun, LI Jun, WANG Mei-yan, FANG Xin-yu

2011, 20(3):  10-19. 

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Restoration of soil water in alfalfa-crop land was simulated in the hilly-arid region of southern Ningxia by a combination of survey and simulation methods. Simulated vertical distribution of soil water in different soil layers was consistent with observations and a good agreement was found between the simulated and observed soil moisture grades in different soil layers. A similar trend (higher speed at the earlier stage and lower speed at the later stage) was found in the process of forming and eliminating the soil desiccation layer. It was difficult for the restoration of soil water in 8-10 m soil. Therefore, soil moisture in this soil layer should not be lower than D grade, i.e. soil water content should not be less than 8.5% during the cultivation process of alfalfa. For the sustainable development of agricultural production, the appropriate alfalfa stand age was 6-8 years; the optimum subsequent cropping system to recover soil water was potato/potato/spring-wheat; and the appropriate cultivation years of this subsequent copping system was 16-20 years before alfalfa was replanted again.

Above-ground Biomass and its relationship to soil moisture of Natural Grassland in the Northern Slopes of the Qilian Mountains

HUANG De-qing, YU Lan, ZHANG Yao-sheng, ZHAO Xin-quan

2011, 20(3):  20-27. 

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Based on the research on the above-ground biomass of natural grassland: alpine pastureland, mountainous meadow, mountainous meadow rangeland, mountainous pastureland, mountainous desert rangeland in the northern slopes of the Mountains Qilian, the results showed that the difference of aboveground biomass among five grassland was significant (P＜0.05), but the curve of seasonal dynamic of aboveground biomass was single apex type and variation trend were same, and it reached the peak value in August. The above-ground biomass of mountainous meadow (100.24 g/m²) is the highest in five vegetation types, and others are in order of mountainous meadow rangeland (71.24 g/m²), mountainous pastureland (70.20 g/m²), alpine pastureland (52.40 g/m²), and mountainous desert rangeland (20.44 g/m²). The result of the Logistic model of above-ground biomass growth curve showed that all grassland types did not reach its maximum the environment can support. The above-ground biomass of different type grassland positively correlated to the accumulated value of precipitation and mean soil moisture. Soil moisture of different soil layers had different impact on the aboveground biomass, but the soil moisture within root distributed soil layers had same impact on aboveground biomass in all grasslands (P＜0.05).

Ecological responses of soil bulk density and water content to different non-grazing patterns in alpine rhododendron shrubland

CAO Wen-xia, XU Chang-lin, ZHANG De-gang, SHI Shang-li, YAO Tuo

2011, 20(3):  28-35. 

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The response of soil characteristics in rhododendron shrubland to different 2-year non-grazing patterns in the Qilian Mountains was studied using soil bulk density and soil moisture characteristics as the main indexes to evaluate herbivore trampling and degraded shrubland recovery. As shrubland soil depth deepened, the soil bulk density increased and soil water content and soil organic matter content reduced. The soils showed obvious heterogeneity; soil bulk density under shrub canopy was less than that under shrub space while soil water content was greater under shrub canopy. The soil bulk density in June was less than those in August and October but soil water content was greater; the soil bulk density showed a very significant negative correlation with soil water content and a positive correlation with soil organic matter. Compared with the traditional shorter summer grazing rest, the non-grazing pattern during the whole growing season had significantly less livestock trampling path features leading to an obvious reduction in soil compaction state, an increase in soil moisture, and an effective improvement of the soil water retaining function. High-intensity grazing in the grass plant withered period also affected the soil conditions for recovery of the rhododendron shrubland. These results confirmed that proper grazing intensity and rest periods should be the main approaches for restoration of degraded alpine rhododendron shrubland.

Effects of sowing methods on the oxidation stability and the chemical bound forms of soil organic carbon in artificial grassland

YANG Heng-shan,TAI Ji-cheng, FAN Fu

2011, 20(3):  36-42. 

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A stratified sampling method was used to study the oxidation stability and the chemical forms of soil organic carbon (SOC) for two-year old alfalfa, for Bromus inermis, and for a mixture of the two. SOC of the alfalfa only was the highest at 0-40 cm, followed by the interlaced mixture. There was a highly significant difference (P＜0.01) compared with the single B. inermis and with the mixture components in the same line. Coefficient of SOC oxidation stability of the interlaced mixture (1.27) was greater than that of the mixture in the same line (1.16). There was a highly significant difference (P<0.01) compared with the single alfalfa (0.99) and the single B. inermis (0.94). It showed that the mixture was beneficial to the oxidation stability of SOC. The chemical bondings of SOC were mainly in the forms of Fe (Al)-bound and under different treatments and at different layers, the content of Fe (Al )-bound SOC was higher than that of Ca-bound SOC (P<0.01).

Spatial pattern analysis of herbaceous community for dominant species and communities in Changzhi wetland, Shanxi

LI Su-qing, WU Dong-mei, WANG Tao, SHANGGUAN Tie-liang

2011, 20(3):  43-50. 

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Spatial pattern analysis of population and community is important to reveal community structure and has become a key topic in modern plant ecology. Changzhi wetland, located in the northwest of Changzhi city, is the largest and best-preserved wetland in Shanxi province, China. Based on field investigations of herbaceous community transects, the method combines detrended correspondence analysis (DCA) ordination technique with a two-term local quadrat variance (TTLQV) method to analyse the herbaceous community pattern of dominant species and communities in Changzhi wetland. Application of the combined methods successfully revealed herbaceous community structure. The community pattern was closely correlated with that of the dominant species. The patterns of Scirpus planiculmis+Phragmites australis and Medicago minima+Paspalum paspaloides were significantly different from each other and the pattern scale gradually decreased with reduced soil moisture, and the herbaceous community patterns of dominant species and communities in Changzhi wetland were not only related to the biological characteristics of species, but were also affected by environmental factors. The small patch scale of dominant species varied from 20 to 290 cm, while the large patch scale usually varied from 900 to 1 270 cm. The results successfully showed the characteristics of species distribution and community structure of Changzhi wetland in Shanxi province.

A preliminary study on carbon dioxide, methane and nitrous oxide fluxes from intertidal flat wetlands of the Yellow River estuary

WANG Ling-ling, SUN Zhi-gao, MOU Xiao-jie, SUN Wan-long, SONG Hong-li, JIANG Huan-huan

2011, 20(3):  51-61. 

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The diurnal variation characteristics of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) fluxes from intertidal flat wetland of the Yellow River estuary were observed in situ with a static-chamber and GC in August 2009. CO₂, CH₄ and N₂O fluxes from the low tidal flat sediment showed an obvious diurnal variation. The flux ranges were from -18.754 6 to 43.730 8, -0.069 8 to 0.224 2 and -0.001 6 to 0.008 3 mg/(m²·h), and the daily average fluxes were 11.629 7, 0.078 7 and 0.004 6 mg/(m²·h), respectively, which showed that the low tidal flat sediment was the source of atmospheric CO₂, CH₄ and N₂O. The flux ranges of CO₂, CH₄ and N₂O in the middle tidal flat sediment were from -30.779 9 to 25.734 2, -0.111 3 to 0.1001 and -0.004 4 to 0.006 3 mg/(m²·h), and the daily average fluxes were 4.569 9, 0.011 3 and 0.002 3 mg/(m²·h), respectively, which showed that the middle tidal flat sediment was also the source of atmospheric CO₂, CH₄ and N₂O. The flux ranges of CO₂, CH₄ and N₂O in the high tidal flat were from 46.253 3 to 102.637 4, -0.210 9 to 0.047 5 and -0.008 3 to 0.007 8 mg/(m²·h), and the daily average fluxes were 76.656 1, -0.037 9 and -0.002 0 mg/(m²·h), respectively, which showed that the high tidal flat was not only the source of atmospheric CO₂ but also a sink for atmospheric CH₄ and N₂O. Further analysis showed that CO₂ flux from the middle tidal flat sediment was significantly positively correlated with atmospheric temperatures (P＜0.05), as was the CH₄ flux from the low tidal flat sediment (0 and 5 cm ground temperatures (P＜0.01)), but the N₂O flux from the middle tidal flat sediment was significantly negatively correlated with atmospheric temperatures and different depths of ground temperatures (5, 10 and 20 cm) (P＜0.05 or 0.01). In addition, sediment solvent and the Suaeda salsa community were the main factors affecting the flux characteristics of CO₂, CH₄ and N₂O, while soil water content and salinity also affected them.

The foundation of a grassland 3D-digital model for Xilin Gol

WANG Rui-yong, QIAO Jiang, YUAN Qing

2011, 20(3):  62-69. 

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To promote the further development of information-based management of grasslands, this work established a grassland three-dimensional digital model based on modern information technology, including 3D-GIS technology, remote sensing technology, simulation technology and other related technologies. The foundation of the 3D-digital model is based upon the Xilin Gol grassland as a demonstration area. The establishment of this digital model is based first on screen grassland information data (maps data and attribute data) according to the principles of grassland ecology; second, an overlay of the layer data filtered to establish the association with attribute data. Finally, the grassland information data was embedded in the three-dimensional virtual space model, to realize queries and analysis of grassland information. The research showed that the grassland three-dimensional digital model developed using the C/C++ language to call OpenGL graphics library works fast and steadily with fast rendering speed, and can provide real-time and dynamic queries of grassland information, and supply technical support for further studies on three-dimensional virtual grassland.

Species diversity of vegetation in relation to biomass and environmental factors in the upper area of the Shule River

CHEN Sheng-yun, LIU Wen-jie, YE Bai-sheng, YANG Guo-jing, YI Shu-hua, WANG Fa-gang, QIN Xiang, REN Jia-wen, QIN Da-he

2011, 20(3):  70-83. 

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The relationship of species diversity with biomass and environmental factors is a hot topic in ecological and environmental sciences. Cryospheric science includes important research concerning the ecological effects of permafrost degeneration. This study provided an analysis of changes in species diversity, community coverage and biomass in relation to elevation gradient, soil physicochemical properties, and depth of permafrost active layer for 21 plots of nine vegetation types in the upper Shule River area of the northeastern Qinghai-Tibet Plateau. There were “Single-hump Type” relationships between species diversity and community coverage as well as biomass, confirming the “Moderate Inflation” theory between species diversity and elevation gradient. In the 0 to 40 cm layers of soils containing high contents of organic matter and total nitrogen, medium levels of available nutrients and with decreases in pH, total potassium and total phosphorus, the community coverage and biomass increased while species diversity initially increased but then decreased. At that time, sedge plants of high feeding value increased, while weed plants decreased. Quantitative analysis revealed that as permafrost degraded, the thickness of the active layer and soil pH both increased, while the contents of organic matter, total nitrogen, available phosphorus and available nitrogen all significantly decreased while total potassium and available potassium increased to a lesser extent but then reduced in the active layer (0-40 cm). As a result there was a gradual change in vegetation composition from wetland plants to mesoxerophytes, and later, to xerophytes. Sequentially, the successive stages changed from alpine marsh meadow to alpine meadow, to “black-soil-beach” grassland and alpine steppe, and eventually to desertified grassland. Along with this process, community coverage and biomass decreased, and sedge plants of high feeding value diminished as a functional group. However, grass, legumes and weeds in plant communities initially increased but then decreased, and species diversity showed the same trend.

Effect of salt stress on physiological and biochemical characteristics of Amorpha fruticosa seedlings

ZOU Li-na, ZHOU Zhi-yu, YAN Shu-yun, QIN Yu

2011, 20(3):  84-90. 

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Physiological characteristics of Amorpha fruticosa leaves, including photosynthetic rate, enzyme activity, organic osmolytes etc. were studied under different soil salt concentrations. The mechanism of salt-tolerance in A. fruticosa is discussed. The net photosynthesis rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and the content of K⁺ decreased with reduced severity of salt stress, while the activities of SOD and POD, the contents of soluble sugar, free praline (Pro) and Na⁺ noticeably increased. The contents of chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (Chl) and carotenoid pigment increased along with the increase in soil salt concentrations, but, the ratio of Chla/Chlb showed no significant change. The results show that the improvement of leaf salt-tolerance in A. fruticosa seedlings resulted from the modulation of physiological characteristics and A. fruticosa had certain salt-tolerant characteristics.

Dynamic changes in the growth and the AsA-GSH circulation metabolism of Chinese cabbage treated with a biogas slurry of water hyacinth

XUE Yan-feng, FENG Hui-fang, SHI Zhi-qi, YAN Shao-hua, ZHENG Jian-chu

2011, 20(3):  91-98. 

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Dynamic changes in the growth and the AsA-GSH circulation metabolism of Chinese cabbage treated with different contents of biogas slurry of water hyacinth were studied in a complete growth cycle. Different responses were found in shoot height and fresh weight when the Chinese cabbages were treated with different contents of biogas slurry. The most obvious effect was observed with 25% biogas slurry. The shoot height and fresh weight significantly increased compared with those of the controls during different sampling periods. However, when the contents of biogas slurry were more than 50%, the shoot height and fresh weight were increasingly reduced with increases of biogas slurry contents. The contents of total Vc, reduced ascorbate (AsA) and dehydroascorbate (DHA) changed differently. With the 25% biogas slurry treatment, total Vc content significantly increased after 45 and 60 d treatment and AsA content also increased even though there was no significant difference compared with that in the controls. DHA content increased considerably during the different sampling periods. When the contents of biogas slurry were more 50%, the contents of total Vc, AsA and DHA were considerably reduced with increases of biogas slurry contents. In the AsA cycle, the activities of ascorbic acid peroxidase (APX), ascorbate oxidase (AAO) and dehydroascorbate reductase (DHAR) showed the same change trend, initially increasing and then decreasing with an increase of treatment duration, i.e. the activities showed the maximum values after 30 d under 25% biogas slurry, whereas the activity of monodehydroascorbate reductase (MDHAR) increased with increased treatment duration. At the same time, the contents of oxidized glutathione (GSSG) and reduced glutathione (GSH) increased significantly with an increase of treatment duration in the GSH cycle. There were significant differences compared with those in the control. The activity of glutathione reductase (GR) increased initially and then decreased with an increase of treatment duration. The activity showed a maximum value after 45 d treatment with the 25% biogas slurry. It is suggested that the optimum biogas slurry content promotes growth,, enhances AsA-GSH circulation metabolism, and maintains higher antioxidative stress capacity in Chinese cabbage.

Physiological responses of Nitraria tangutorum from different geographic provenances under osmotic stress

GAO Ming, LI Yi, CHONG Pei-fang, SU Shi-ping

2011, 20(3):  99-107. 

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Nitraria tangutorum was taken from three geographic provenances (Wuwei, Zhangye and Jiuquan) and several physiological characteristics were measured under PEG stress. Under PEG osmotic stress, the contents of malondialdehyde (MDA), proline (Pro), soluble sugar (SS) and soluble protein (SP), and superoxide dismutase (SOD) activity increased, while the relative water content (RWC) reduced and catalase (CAT) activity inbitially increased but then decreased. There were significant differences (P<0.05) between PEG treatment and the control in most indexes, but not between SOD activity and the control. Correlation analysis showed that there were highly significant correlations of MDA content with SOD activity and with the contents of Pro, SP, and SS. There were highly significant negative correlations of RWC with SOD activity and with the contents of Pro, SP, SS and MDA. There were highly significant or significant correlations between SOD activity and the contents of Pro, SS and SP. Principal component analysis showed that the first principal components of N. tangutorum osmotic stress were RWC and the contents of Pro, SS, SP and MDA while the second and third were SOD and CAT, respectively. Under PEG stress, drought tolerances of plants from the three geographic provenances were in the sequence: Jiuquan>Zhangye>Wuwei.

Effects of PEG stress on physiological characteristics of Calligonum mongolicum in different geographical provenance

QIU Zhen-jing, LI Yi, CHONG Pei-fang

2011, 20(3):  108-114. 

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To simulate the solution drought stress condition with different concentrations PEG-6000, we studied the effects of drought-resistant of physiological characteristics in Calligonum mongolicum seedlings from different geographical provenance in Gansu province. The results indicated that content of Pro increased with the stress time prolong, content of SS(soluble sugar) raised first, then declined, and increased continually later, content of MDA(malondehyde) increased first and then decreased, SOD(superoxide dismutase) activity presented “M” tendency, POD(peroxide enzyme) activity increased first and then decreased. The seedlings of three geographical provenances generally presented a similar tendency under different concentrations and long-term stress while with the significant difference(P<0.05).The increasing range of Pro content was Wuwei>Jiuquan>Zhangye, soluble sugar content was Jiuquan>Zhangye>Wuwei, MDA content was Wuwei>Zhangye>Jiuquan, SOD activity was Wuwei>Zhangye>Jiuquan, POD activity was Jiuquan>Wuwei>Zhangye. There existed difference of drought resistance mechanism of C. mongolicum,but the adjustment of protection enzymes was an important physiological reaction to the environment adaptability.

Effect of periodic defoliation on clonal growth in Axonopus compressus

LI Jie-ying, XIE An-xia, BAI Chang-jun, LIAO Li, HUANG Xiao-hui, WANG Zhi-yong

2011, 20(3):  115-121. 

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The clonal growth of carpet grass (Axonopus compressus) under periodic defoliations was studied in this randomized block experiment. There were significant, or very significant, differences between periodic defoliations and the optimum growth of carpet grass when the leaves were moderately pruned. Too high or low frequently of leaf cutting (D10 or D60) inhibited the normal growth of carpet grass and led to lower quality turf. However, moderate defoliation could contribute to clonal growth of carpet grasses and improve their ornamental value.

Research on nutrition evaluation of Yumu No.1 alfalfa in rabbit

GUO Zhi-qiang, SONG Dai-jun, YU Yong-xiong, XIE Xiao-hong, YI Jun, ZHANG Jia-hua, LEI Min

2011, 20(3):  122-127. 

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This study was aimed at elaborating the nutritional value of new varieties of alfalfa(Medicago sativa), and providing nutritional parameters for the adaption of alfalfa in the South of China. Growth properties, general nutrition of alfalfa hay and digestibility on five different growth periods (vegetative stage, bud stage, early flowering, flowering and podding stage) of Yumu No.1 alfalfa were studied. There was a significant influence on the nutrition of alfalfa hay in different periods(P＜0.05). The leaf/stem ratio, fresh/dry ratio, crude protein, ether extract, ash and calcium decreased in turn switching from the nutrition stage to the pod-besring period. The whole variation trend is quick-slow-qiuck, characterized as “chair-type”. The phosphorous decreased while the content of neutral detergent fiber, acid detergent fiber and acid detergent lignin increased from the nutrition stage to the pod-besring period. The whole trend showed fast-slow-fast anti-chair-type shape. The digestibility of alfalfa hay, digestible energy, crude protein, ether extract, ash, neutral detergent fiber, acid detergent fiber decreased in turn from vegetative stage to podding stage. Nutritional composition and digestibility of early flowering and flowering of Yumu No.1 alfalfa had no significant differences(P＞0.05),which was different from the northern alfalfa hay. The nutrition composition digestibility of the alfalfa hay has a positive correlation with the protein content while a negative correlates with the ADL content. The influence of harvest time and variety on digestibility actually resulted from the combined effect of the protein of alfalfa hay and the content of acid detergent fiber.

Functional development of forestomach in confined lambs at the age of 0－56 d

GUO Jiang-peng, PAN Jian-zhong, LI Fa-di, HAO Zheng-li, MA You-ji, ZHANG Yuan-xing, LI Hai-jing, MA Teng

2011, 20(3):  128-135. 

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Forty-five male lambs (Gansu modern breeding sheep group) were divided into 9 treatments (5 animals in every treatment), killed and sampled at 0, 7, 14, 21, 28, 35, 42, 49 or 56 d respectively. The relative weight and pH value of contents in every compartment of forestomach, concentration and Molar proportion of volatile fatty acids, and activity of microbic enzymes of rumen contents were measured. The relative weight of contents (%total weight of content in stomach) in reticulorumen were linearly increase during 0 to 35 d(R²=0.93,P=0.00), and was 61.54% and 76.87% at 28 and 35 d respectively. There was lower pH value in contents of rumen, reticulum and omasum, it was changed between in 5.30 to 6.03, 5.37 to 6.42 and 5.39 to 6.15 respectively. It was mainly acetic acid fermentation type, and the ratio of acetic to propionic (A/P) was changed between 2.18 to 3.82 in rumen contents, and there was higher propionic concentration. The higher activity of protease, α-amylase, cellulase in rumen contents was respectively appeared at 21, 7 and 14 d. The functional development in forestome was preliminarily completed at 28 d in the conditions of this trial. With confined raising and supplying the suited supplementary diet from 7 d age in days, the early weaning technology may be used at 35 or 28 d after birth in lambs.

Effect of different combinations of diet on rumen metabolic parameters of sheep

LI Yong, HAO Zheng-li, LI Fa-di, ZHENG Chen, ZHANG Xiao-qing, WU Qiu-jue, YE De-he

2011, 20(3):  136-142. 

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Three one-and half year old Gansu high mountain fine wool wethers (average live weight 22.5 kg) per treatment were fitted with permanent rumen fistula, and used in a 3×3 Latin square design to study the effects on rumen metabolic profiles of three different diet combinations: Control, 8% dried beet pulp supplement, and 8% apple pomace supplement. Each of the three diet circulatory periods included 10 d for preliminary testing followed by 9 d for sampling during the whole experiment. The average pH value of rumen liquid was similar in all treatments (P＞0.05). The propionic molar ratio of rumen liquid of sheep fed with diet Ⅱ tended to be lower (P=0.109), and the ratio between acetic and propionic was higher for Ⅱ than for Ⅰ (P＜0.05) and Ⅲ (P＞0.05), but the rumen fermentation in all treatments belonged to the acetic acid type. The time changes of TVFA for diet Ⅱ had a similar parabola, and the highest values of TVFA for diets Ⅰ and Ⅲ were measured at 3 or 5 h after feeding respectively. There were no significant differences between the three treatments (P＞0.05) in the means of total N, protein N, NH₃-N, urea N, and the concentrations of bacterial N in rumen fluid. For diet Ⅱ, the concentrates of total N were always higher with two peaks observed at 3 and 5 h after feeding, but the NH₃-N levels were lower and the peak appeared 1 h after feeding. All the highest values of total N for Ⅰ and Ⅲ were measured at 7 h after feeding, and the peak of NH₃-N was observed at 1 and at 7 h after feeding for Ⅲ, but not for I. It is suggested that there were no significant differences in the types of rumen fermentation and in the efficiencies of nitrogen utilization among the three treatments but diet Ⅱ showed some superiority, for stabilizing rumen surroundings, maintaining fibrolytic activity and utilizing N compared with Ⅰ and Ⅲ.

Effect of Lactobacillus buchneri on the quality and aerobic stability of green corn-stalk silages

LV Wen-long, DIAO Qi-yu, YAN Gui-long

2011, 20(3):  143-148. 

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The effects of Lactobacillus buchneri on silage quality of green corn-stalks was studied. Inoculation rates of L. buchneri were: 0, 3.05×10⁴, 3.05×10⁵, 3.05×10⁶ cfu/g, under CS, CSL, CSS, and CSH. Sampling and determination of chemical composition was done on the 1st, 16th, 34th and 60th day after ensiling. Inoculation of L. buchneri increased pH value and acetic acid content, whereas, both lactic acid content and the ratio of lactic acid to acetic acid decreased, resulting in the promotion of aerobic stability of silage.

The quality of silage in Inner Mongolia

WANG Xiao-na, SUN Qi-zhong, HAN Hai-bo, ZHANG Xiao-qing, SUN Chang-le

2011, 20(3):  149-155. 

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In order to understand the current situation of silage in Inner Mongolia, on the one hand from Inner Mongolia silage production of hands on the other hand from the silage mass quality determination, on the situation in Inner Mongolia silage for analysis summary. Inner Mongolia silage modulation and storage are able to follow the silage norms, its main storage device to store storage and moat, silage storage time is 9 months, silage species there are whole corn silage, Corn Stover, beet silage, etc. Mongolia silage mass quality overall better, through the production of fine grade rating reached accounted for 83% of the total sample, in three kinds of silage corn stover silage in nutritional quality or fermentation quality were significant (P<0.05).

Genetic variation of Medicago sativa callus revealed by the ploidy analyser

GENG Xiao-li, WEI Zhen-wu, YAO Xi-hong

2011, 20(3):  156-161. 

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DNA contents of callus of three genotype and eight culture time, which derived from anther culture in Medicago sativa, were detected by flow-cytometric analysis. The percentage of S stage cells and percentage of DNA content variation cells were analysed by the Data Pool Application of Cytometre software, the relationship between the callus cultivating time and the DNA content variation were analysed by the SPSS 10.0 software. One purpose of the study is to seek the relationship between DNA content variation and the culture time, and another is to provide the basic study of the law of DNA content variation in M. sativa for further research. DNA content of 24 samples were all changed and all DNA doubled. By the SPSS 10.0 software analysed, the correlativity between percentage of DNA content variation cells and cultivating time in M. sativa were found. With the increase of cultivating time, chromosome mutation were added. However, the trend was not always unchanged. The 0-12 week was the concentrated occurring stage of M. sativa callus DNA content variation, whereafter, DNA content variation become smooth with the increase of subculture times.

Phylogeny of Elymus sensu lato in Triticeae (Poaceae) based on plastid trnL-F sequence data

ZHANG Chun, FAN Xing, SHA Li-na, KANG Hou-yang, ZHANG Hai-qin, ZHOU Yong-hong

2011, 20(3):  162-173. 

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The genus Elymus sensu lato includes Roegneria, Elymus, Hystrix, Sitanion, and Kengyilia. The plastid trnL-F sequence data were analyzed for their phylogenetic relationships, maternal donor, and for the origin and differentiation of St genomes by using Maximum Parsimony (MP) and Median Joining algorithm (MJ) methods. 1) The maternal donor of Elymus sensu lato was not always Pseudoroegneria. The P genome served as the maternal donor to Kengyilia melanthera and K. thoroldiana, while the Ns genome was the maternal donor for Hystrix duthiei and H. duthiei ssp. longearistata; 2) The MP tree revealed the close relationships between P, W and St genomes, while the H and Ns genomes were distinctly related to them; 3) K. melanthera and K. thoroldiana were clustered with diploid Agropyron species, which indicated the close relationships among them. H. patula was clustered in the St clade, while H. duthiei and H. duthiei ssp. longearistata were grouped in the Ns clade. The genomic constitution of H. patula was different from H. duthiei and H. duthiei ssp. longearistata; 4) The five diploid species with St genome did not form the monophyletic clades, suggesting the differentiation of the diploid species. The polyploid species with St genome were not clustered together, suggesting the differentiation of St genomes in polyploids; 5) The species distributed in Eurasia might originate from the diploid species of Pseudoroegneria from Asia, while the North American species might originate from North America Pseudoroegneria species. Some species might have a multiple origin and experienced recurrent hybridization between species with different genomes.

Effects of anti-browning agents on the induction of sudangrass callus

LV Zong-you, SU Yan-jing, ZHAO Guo-qi, WU Cai-xia

2011, 20(3):  174-181. 

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Sudangrass can easily produce phenolic compounds when it is grown in tissue culture. The browning phenomenon is harmful to callus growth, leading to callus death. Anti-browning agents were used to study browning. Active carbon(AC), vitamin C(V_C), polyvinyl pyrrolidone(PVP), and AgNO₃ all improved the number of inductions and reduced the numbers browning. Low concentrations of sucrose (10-20 g/L) reduced the numbers browning but did not improve the induction number, while high concentrations increased both. Citric acid improved only the induction numbers and did not affect the numbers browning. When the concentration of AC was 0.15 g/L, the callus was best both in terms of induction number and anti-browning.

A study on genetic diversity of reproductive characters in Elymus nutans germplasm resources

ZHANG Miao-qing, WANG Yan-rong, ZHANG Ji-yu, LIU Zhi-peng, ZHANG Lei, NIE Bin, ZHOU Jing

2011, 20(3):  182-191. 

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Genetic diversity of six reproductive characters was studied in 50 Elymus nutans populations collected from various regions of Gansu, Qinghai and Sichuan provinces in China. The characters included ear length, ear width, spikelet number per ear, seed length, awn length and thousand-seed weight. Shannon-Weaver index analysis showed that there was an abundant genetic diversity (H′=1.873) among populations. The genetic variation within populations (63.8%) was greater than that between populations ( 36.2%). Genetic variation was different for each character, that for ear width (CV=0.347 2) was the greatest while seed length (CV=0.118 4) was the smallest. The 50 populations were divided into three groups by cluster analysis. All reproductive characters were correlated to various extents with altitude, latitude, longitude, mean annual temperature and annual precipitation. Ear length and spikelet number per ear were highly significantly correlated with altitude and mean annual temperature (P<0.01). Plans for the utilization and protection of E. nutans are proposed.

An approach to detect the low-abundant proteins in rice leaf sheath

WANG Ying, CUI Wei-tong, YANG Ming-feng, SHEN Shi-hua

2011, 20(3):  192-197. 

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Enrichment of low-abundant proteins and their detection still remain great challenges in proteomics research. The existence of high-abundant proteins, e.g. ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) in plants, leads to this dilemma. The high-abundant proteins engage a large proportion of the whole-cell proteins and thus make the low-abundant proteins poorly detectable by 2-DE. In this report, we used a protocol for the preparation of whole-cell proteins through polyethylene glycol (PEG) precipitation, to develop an approach of identifying low-abundant proteins in rice leaf sheathes. In a comparison of the 2-DE analyses of protein samples prepared using the Mg/NP-40 method without PEG fractionation, with the 15% and 20% PEG fractionation protocol, a relatively high reproducibility was achieved using the 20% PEG fractionation protocol in terms of protein species and low-abundant proteins.

Studies of biological traits and karyotype of two barnyard grass variety

WU Shu-ju, LI Xin-ling, TANG Feng-lan

2011, 20(3):  198-204. 

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In order to provide a theoretical basis for further study and utilization of barnyard grass resources, the agronomic traits and karyotype of Large head barnyard grass (005) and goose head barnyard grass (031)were studied in 2007. The two barnyard grass (Echinochloa crusgalli) variety were collected from different locations of Heilongjiang province. During the growth period, plant height, tiller number, leaf area, fresh weight, dry yield, and other major agronomic traits were determined and the actual production of the plot was tested. That the agronomic trait of two barnyard grass variety were good and fresh forage and hay yield have no significant differences under the current climatic condition in Heilongjiang province. Karyotape analysis indicates that the nucleus chromosome number of two barnyard grass variety are 2n=54. Large head barnyard grass is 2n=46m+8sm, Goose head barnyard grass is 2n=44m+10sm.

A study on the genetic law of seed coat characters in hull-less Cucurbita pepo

XUE Ying-yu, SHI Gui-ying, XU Bing-liang, CHEN Rong-xian

2011, 20(3):  205-210. 

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The seed coat trait of Cucurbita pepo was classified into two types, seed-hulled and seed-naked. Experiments were performed to study the inheritance pattern. Three inbreeds with hulled seed, 04FC409-4, 03N-122-19 and 04LAg-26-2, and three inbreeds with hull-less seed, 04GD112-7, 1N-275-7 and 04LAg-26-28, were used as the parental lines in the mating patterns 04FC409-4 and 04GD112-7, 03N-122-19 and 1N-275-7, 04LAg-26-2 and 04LAg-26-28. In the F₁ generations, all the plants were seed-hulled. However, in the F₂ generations, segregation of hulled and hull-less seeds showed the ratio of almost 3 to 1. For the backcrosses, all the BC₁ and F₁ (the inbreed with hulled seed used as recurrent parent) generations appeared seed-hulled. But in the BC₂ and F₁ (the inbreed with hull-less seed as recurrent parent) generations, segregation of hulled and hull-less seeds showed the ratio of almost 1 to 1. So it was concluded that each of the hulled seed and hull-less seed in C. pepo was controlled by one pair of different nuclear genes and “seed-hulled” was dominant to “seed-hull-less”.

Genome-wide analysis of the WRKY transcription factor family in Medicago truncatula

JIANG Teng, LIN Yong-xiang, LIU Xue, JIANG Hai-yang, ZHU Su-wen

2011, 20(3):  211-218. 

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Medicago truncatula is a model Leguminosae plant because it has a small genome, is easily transformed, and its genome has been completely sequenced. WRKY transcription factor is a new protein family containing conserved WRKYGQK amino acid sequences. Regulator genes and (/or) functional genes containing a W-box in the promoter are regulated. WRKY proteins correlate to plant defense response. M. truncatula genome sequence (Mt2.0) was employed in this research. The gene number, class, phylogenetic relation and conserved motif of WRKY transcription factor genes were analysed in M. truncatula. Twenty-eight WRKY genes were found in M. truncatula, two domains were confirmed in five WRKY genes and 33 WRKY domains were found in all WRKY genes. The number of genes is less than those of Arabidopsis and rice. Phylogenetic trees show different evolution patterns of Arabidopsis, rice and M. truncatula. WRKY genes have a unique evolutionary mechanism in Medicago. WRKY proteins were found to contain 33 conserved motifs by using MEME analysis, and five motifs were affirmed in WRKY domains. The study provides a foundation for function and evolution of WRKY genes in M. truncatula.

Influences of different phosphorus concentrations on the root distribution of Stylosanthes and black seed Paspalum

YU Ai, YANG Fan, ZHANG Yu, WU Yan-long, LU Qing-fu, TANG Shu-mei

2011, 20(3):  219-224. 

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Using a root-boxing and root scanning measurement system, the leguminous forage grass, Stylosanthes and the Graminaceous forage grass black seed Paspalum, were used to study the effect of phosphorus concentration on root distribution. Root biomasses of grasses significantly decreased with soil depth. The roots of Stylosanthes were concentrated in the 0-10 cm layer and those of the black seed Paspalum in the 0-20 cm layer. The black seed Paspalum had a higher demand for phosphorus and responded more to added phosphorus. For Stylosanthes, a low concentration of phosphorus (0.48 g P₂O₅/kg soil) is more suitable for the root and aboveground growth than a high concentration (1.92 g P₂O₅/kg soil). For the black seed Paspalum, an appropriate increase in the amount of phosphorus into the soil, can increase the root and aboveground dry weight, total root length, root surface area, volume and root average diameter.

Effects of green manure application on the microbial biomass C and N contents and of the enzyme activity of tobacco-planting soil

LI Zheng, LIU Guo-shun, JING Hai-xia, XIE Chang-sheng, XIANG Yong-guang, YANG Chao, ZHENG Wen-ran, YE Xie-feng

2011, 20(3):  225-232. 

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Field experiments were conducted to study the effects of green manure application on microbial biomass C and N contents and of the enzyme activity of tobacco-planting soil. The application of green manure increased the soil microbial biomass C and N contents and the activities of soil urease, acid phosphatase (ACP), sucrase, catalase. The trend of increase returning 22 500 kg/ha was more greater than the others. Compared with the control at different growth stages, the soil microbial biomass C and N contents increased 66.09%-161.28% and 76.88%-257.10%, respectively. The activity of soil urease, acid phosphatase (ACP), invertase and catalase increased 31.88%-54.05%, 11.15%-17.62%, 16.05%-101.06% and 41.38%-71.43%, respectively. These results show that application of green manure promoted the activity of soil organisms, thus favouring the turnover of organic matter in the soil and the provision of nutrition to meet the needs of tobacco plants normal growth. The dynamic changes of soil microbial biomass C and N contents and of the enzyme activity within the tobacco developmental period showed that microbial biomass C and N reached a peak at the rosette stage of flue-cured tobacco. However, the peak of soil enzyme activities appeared at the busy stage, and when the crops were in bloom. The dynamic changes of microbial biomass C and N contents and of enzyme activity varied at different growth stages, suggesting that changes of soil enzyme activity and nutrient release from green manure were highly related with soil nutrient supply. The microbial biomass C and N contents and enzyme activity could be used as biological indices of soil quality. The relationship of the whole decomposition process of green manure with growth was coordinated with nutrient uptake of flue-cured tobacco. This study provides a theoretical basis to study low-carbon agriculture and build resource-saving, environment-friendly agriculture and promote the sustainable development of tobacco agriculture and the production of tobacco leaf with specific characteristics.

Effects of different nitrogen levels on photosynthetic characteristics, dry matter accumulation and yield of relay strip intercropping Glycine max after blooming

YAN Yan-hong, YANG Wen-yu, ZHANG Xin-quan, CHEN Xiao-lin, CHEN Zhong-qun

2011, 20(3):  233-238. 

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In the relay strip intercropping system of “Zey mays-Glycine max”, the G. max cultivar, Gongxuan 1, was used to study the effects of different nitrogen levels on photosynthetic characteristics, dry matter accumulation and yield of G. max after blooming. The results showed that the optimal treatment on the Chl a content, Chl a/b ratio, net photosynthetic rate (Pn), the dry weight of leaf blade, leaf stalk, stem and pod and the total above-ground biomass after blooming was the lower nitrogen level (32.4 kg/ha), followed by the middle nitrogen level (64.8 kg/ha). The optimal treatment on the yield and number of pods was also the lower nitrogen level, which were 18.22% and 17.37% higher than those in the controls respectively, the difference was very significant; followed by the middle nitrogen level; those of the higher nitrogen treatment (97.2 kg/ha) were significantly lower than those in the controls, which was due to the higher leaf area index (LAI) for high nitrogen treatment to result in hindering ventilation and transmission light. So, the appropriate nitrogen (32.4, 64.8 kg/ha) could improve the net photosynthetic rate (Pn) and the total above-ground biomass, accordingly improve yield.

Plant nitrogen content of annual ryegrass and spectral reflectance response to nitrogen application level

YANG Hong-li, CHEN Gong, WU Jian-fu

2011, 20(3):  239-244. 

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Plant nitrogen content was a vital indicator to evaluate pasture growing situations, to estimate production and to determine optimal fertilizer application. An experiment was conducted to investigate the plant nitrogen content of annual ryegrass and the characteristics of canopy spectral reflectance under five nitrogen levels, exploring the relationship between plant canopy reflectance and nitrogen content. The nitrogen level had a significant impact on the plant nitrogen content of annual ryegrass and when nitrogen fertilizer increased from 100 to 400 kg/ha the plant nitrogen content increased accordingly. In the visible region, canopy spectral reflectance rate reduced as nitrogen level increased. There was significant negative correlation between plant nitrogen content and single-band reflectance rate and the absolute value of the correlation coefficient was greater than 0.5 (P<0.01) within 487-718 nm. The optimal model of plant nitrogen content estimation by using sensitive bands was y=4.362-0.754x₅₇₉+0.351x₇₀₀, and the optimal model of plant nitrogen content estimation based on vegetation index was y=3.026-0.670DVI_(610,487)+4.997NDVI_(700,579). A strong correlation between estimated and true value of plant nitrogen content was detected (P<0.01).

History, theory and practice of pasture-crop rotation in China: A review

XING Fu, ZHOU Jing-ying, JIN Yong-jun, SUN Lu, ZHANG Jian-feng, YUE Wei, BAO Zhuang, NI Nan, QIAN Ying

2011, 20(3):  245-255. 

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The vigorous implementation of pasture-crop rotation is of great significance to the current agricultural structure adjustment and agricultural sustainable development in China. This paper summarizes the developmental history of Chinese agriculture, from continuous cropping systems to pasture-crop rotation, and recapitulates the ecological and economic benefits of pasture-crop rotation such as increasing output, reducing weeds, pests and diseases, improving soil fertility, maintaining water and soil. Seven existing major pasture-crop rotation models in China such as the “ryegrass→rice” rotation in south Asian tropics of China are summarized. The energy-driven pasture-crop rotation becomes necessary, according to the theory of agro-grassland system, for combining national food security, agricultural structure restructuring, water-soil conservation, and the demand for wealth. The feasibility of implementing pasture-crop rotation for policy assurance, theoretical guidance and technical support are also discussed. The focus should be put on strengthening the pasture-crop rotation models and demonstration research with regional representation, and with breeding crops and pastures to meet the needs of future pasture-crop rotation. The gains and losses from the two “herbage seed upsurge” should be compared.

Progress of research on △12 fatty acid desaturases and their coding genes

LIU Yong-hong, ZHANG Li-jing, ZHANG Hong-rong, FU Hua

2011, 20(3):  256-267. 

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△12 fatty acid desaturases (fad2) are key enzymes which catalyze the introduction of double bonds at the delta 12 position in the hydrocarbon chain and thereby convert oleic acid to linoleic acid. They control the synthesis of oleic acid, linoleic acid and other polyunsaturated lipids in plant cells. △12 fatty acid desaturases are categorized into fad2 and fad6 type according to their different electron donors. fad2 type can be further categorized into housekeeping-type and seed-type fad2. fad2 and fad6 types have the same functionality but different genetic relationship. In this article, recent research advances on △12 fatty acid desaturases in terms of their structure and function, classification, evolutionary system, physiological function, gene cloning, gene structure and copy number in plants are reviewed. The directions of the relative research field are also discussed.

Invasion mechanism and ecological management of exotic plant, Flaveria bidentis

ZHANG Tian-rui, HUANGFU Chao-he, YANG Dian-lin, BAI Xiao-ming

2011, 20(3):  268-278. 

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Flaveria bidentis, an annual exotic weed invaded China in recent years, has caused huge damage to the ecological environment with its strong ability to reproduce and invasive nature. At the same time, its invasion also threatens the safety of agricultural ecology. Based on this knowledge, recent research in its invasion mechanism and ecological management measures were summarized in this paper. Firstly, allelopathic properties and the rapid adaptive traits of F. bidentis may contribute to its strong invasion and wide distribution. Secondly, F. bidentis can cause soil-based ecosystem processes change following its invasion, and such changes could establish positive feedbacks, which further enhance its successful spread in turn. As a result, the invasion of F. bidentis has profoundly influence nutrient cycling, enzyme activities and microbial community composition and function as well. Finally, based on the fundamental ecological principles underlying succession, it was proposed that the competitive ability of native vegetation should be established through restoration activities in order to reduce the proliferation of F. bidentis, and the selection of competitive candidate plant species well adapted to restoration site conditions are important keys to success. On this basis, the further researches needed for F. bidentis was also proposed for its wise management and possible utilization.

Locoweed and advances in research on toxic components

GAO Xin-lei, HAN Bing, ZHAO Meng-li, HE Jiang-feng, YU Ting

2011, 20(3):  279-286. 

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Locoweeds are poisonous plants of Astragalus spp. and Oxytropis spp. in the family Leguminosae. They contain the toxic indolizidine alkaloid swainsonine, which causes livestock poisoning known as ‘locoism’. Locoweeds are widely distributed in the world and cause a retrogressive succession, grazer poisoning, and death in the rangelands of some areas, thus seriously threatening grassland agriculture. The toxicity of locoweed was attributed to swainsonine a metabolite of fungal endophytes in locoweed, and in medicine as antineoplastic agents. The distribution, harmfulness, prevention, toxic components and advances in research on locoweeds are reviewed, and studies on taxonomy and the prospect of using locoweeds are discussed.

Effects of different mulching on the establishment of Cleistogenes songorica

TAI Jian-hui, WANG Yan-rong, LI Xiao-xia, WEI Xue, CHEN Gu

2011, 20(3):  287-291. 

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Effects of different mulching on the seedling establishment of Cleistogenes songorica varied with soil water conditions. The mulches showed no effects on seedling establishment when the plants were irrigated every 5 days, but it significantly affected seedling survival rate when the plants were irrigated every 15 days. At 15-day interval irrigation, the seedling establishment rate was the highest (40.7%) under sand mulching and was the lowest (15.9%) under straw mulching. The seedling establishment rate under film mulching (23.6%) was not significantly different from that of the control (22.2%), but was significantly greater than that under straw mulching (15.9%). The plant heights, leaf numbers, tiller numbers, leaf areas and aboveground biomasses under sand mulching were significantly greater than those under other treatments.

Production and RAPD verification of T₀ salt-tolerant alfalfa introducing the total DNA from Rhizophora apiculata by the pollen-tube pathway

ZHANG Li-quan, NIU Yi-ding, HAO Jin-feng, HASI Agula

2011, 20(3):  292-297. 

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The exogenous total DNA of Rhizophora apiculata was introduced into alfalfa (Medicago sativa) by the pollen-tube pathway. In this study, 1 391 flowers were treated and 894 transformed T₀ seeds were harvested. Twelve T₀ seedlings with improved salt-tolerance were obtained when the T₀ seeds were planted in MS medium containing 225 mmol/L NaCl. RAPD analysis of T₀ seedlings, receptor and donor were carried out. Eight primers which could amplify steady and clear bands were chosen from 55 arbitrary primers tested, and increased band diversity with new bands, specific bands in donor and deletion in receptor. It showed that the exogenous DNA was conformed for integration into the receptors genome, and the improved salt-resistance of T₀ seedlings may be related to the introduction of exogenous genes.

A study on soil fungal diversity of Solanum rostratum-invaded and non-invaded areas in Liaoning province

QU Bo, ZHU Ming-wei, YANG Hong, LI Nan, CHEN Xu-hui, ZHANG Guo-liang, FU Wei-dong, LI Tian-lai

2011, 20(3):  298-303. 

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Soil fungal diversity and numbers were analysed in Solanum rostratum-invaded and non-invaded areas in Liaoning province from 2008 to 2009. One hundred and fifty soil samples were collected and cultured with the soil plate method. All the species were identified and divided into 30 genera, of which Penicillium, Aspergillus, Trichoderma, Mucor, Rhizopus and Fusarium were the dominant groups of the S. rostratum-invaded areas. According to the Jaccard index of similarity theory, the similarity level of the soil fungal communities was medium between the invaded and non-invaded areas. C_j values were between 0.50 and 0.75. Soil fungal diversity was not significantly different between invaded and non-invaded areas. From the soil fungal flora, it is probable that S. rostratum spread to non-invaded areas.

Effect of sparse sowing of large whole tubers on the yield and agronomic traits of potato

LIN Hai-ming, ZHOU Jian-jun, WANG Di, ZHANG Jun-lian, LV Xing-mi, LI Song

2011, 20(3):  304-308. 

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The use of large, whole potato tubers as seed potatoes to increase potato yield and the effect of sparse sowing of these tubers on the main agronomic traits and the yield-increasing potential were studied in a field experiment. Sparse sowing increased seedling rate, main stem number, plant height, tuberization rate, fresh tuber weight, leaf area index (LAI), yield and commodity rate. Sparse sowing was significantly different from cut tuber sowing. A comprehensive comparison showed that there was a stronger yield-increasing potential by using sparse sowing, and the main agronomic traits were also improved, a promising perspective for extending this technique. The yield increase was greatest when whole tuber weights were 140-160 g per potato at a planting density of 27 779 plants per hectare. The application of a combination of the two treatments is suggested for potato production.