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    20 May 2015, Volume 24 Issue 5
    Vegetation index feature change and its influencing factors and spatial-temporal process analysis of desert grassland in the Ebinur Lake Nature Reserve, Xinjiang
    WANG Lu, DING Jian-Li
    2015, 24(5):  4-11.  DOI: 10.11686/cyxb20150502
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    This research investigated the vegetation of the Ebinur Lake Nature Reserve, Xinjiang, a typical desert-oasis ecotonein northen China. After radiometric and geometric correction, Landsat remote sensing images from 1990, 1998 and 2011 were used for the study. The classification of land cover based on a decision tree approach was implemented using the normalized difference vegetation index (NDVI) and the vertical zonal vegetation distribution. Annual rainfall and the average annual temperature data of four meteorological stations were utilized. The NDVI was generally highest in the piedmont desert grass and lowest in desert areas; piedmont desert grass>desert steppe>saline meadow>herbaceous swamp>desert. The area of land influenced by salinization appeared to be increasing. Over the 20 year period mean temperatures showed an increasing trend, consistent with the global warming trend. Temperature did not influence NDVI but rainfall was positively correlated with NDVI. It was concluded that the establishment of the Ebinur Lake Nature Reserve has significantly reduced land degradation and that government policy plays a significant role in the protection of desert environments.
    Assessment of drought disaster risk in southern China
    WANG Ying, SHA Sha, WANG Su-Ping, WANG Jin-Song, YAO Yu-Bi
    2015, 24(5):  12-24.  DOI: 10.11686/cyxb20150503
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    A critical element of risk management is drought risk assessment. Through in-depth analysis of factors linked to drought risk, and application of principles of natural disaster management, a drought disaster risk assessment model was constructed. The model assesses the level of danger posed by the disaster-inducing factors, the vulnerability of the disaster-prone environment, the level of exposure of the territorial body, and disaster prevention and mitigation capabilities in place. The model was then used to conduct an assessment of drought risk for the southern part of China using GIS data and local meteorological, geographical environment and socio-economic data. The model indicated: 1) the higher risk areas for disaster-inducing factors are mainly in the mid-east of Yunnan province, on the boundary between Yunnan and Sichuan province, the mountain area of western Sichuan, the basin of eastern Sichuan and the eastern coastal area of Guangdong; 2) The more disaster-prone areas are mainly in the mid-east of Yunnan, the eastern Sichuan basin and northwestern Guizhou province; 3) The territorial bodies with greatest exposure are mainly in the eastern, coastal area and Leizhou peninsula of Guangdong province, the southern region of Guangxi province and the Sichuan basin; 4) Higher regional disaster prevention and mitigation capabilities are mainly found in western Chongqing, western Sichuan, northeastern Yunnan, central Guizhou, southern Guangxi and mid-east of Guangdong province; 5) Zones with high drought disaster risk are mainly in the eastern Sichuan basin, on the boundary between Yunnan and Sichuan, in northeastern Yunnan, southwestern Guangxi, northeastern Guangdong and the Leizhou peninsula. Zones with low drought disaster risk are found mainly in the eastern mountainous areas of Sichuan, and in eastern Guangdong and Guangxi provinces.
    Comprehensive evaluation and risk assessment of grasshoppers’habitat based on a projection pursuit model
    HUANG Xun-Bing, WU Hui-Hui, QIN Xing-Hu, CAO Guang-Chun, WANG Guang-Jun, NONG Xiang-Qun, TU Xiong-Bing, Gexigeduren, HE Bing, Eerdengbatu, Wuyahan, ZHANG Ze-Hua
    2015, 24(5):  25-33.  DOI: 10.11686/cyxb20150504
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    There are close and complex relationships between grasshopper occurrence and habitat vegetation. A comprehensive analysis of these relationships will provide a stable foundation for risk assessments of grasshopper infection. Grasshopper population density and 21 vegetation parameters were analyzed in the survey on which this paper is based. A projection pursuit model was developed and verified in order to evaluate the risks of grasshopper infection. Results showed that a low index for plant biomass diversity had the greatest influence on grasshopper density, with the best projection direction a at 0.6725. Poaceae dominance with a high index had the greatest influence on Oedaleus asiaticus density, with the best projection direction a at 0.6547. There was a significant linear relationship (P<0.01) between the projection eigenvalue (Zi) and grasshopper density (y=48.861x-18.937, R=0.9509). The occurrence of grasshoppers can be predicted according to the projection eigenvalue (Zi). The bigger the value of Zi, the higher the risk of grasshopper occurrence. The projection pursuit model can be used to eliminate the effect of irrelevant variables. Its application will play an important role in monitoring and early warning for the ecological management of grasshoppers.
    Vegetation and soil microorganism characteristics of degraded grasslands
    LU Hu, YAO Tuo, LI Jian-Hong, MA Wen-Bin, CHAI Xiao-Hong
    2015, 24(5):  34-43.  DOI: 10.11686/cyxb20150505
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    Currently,studies of grassland degradation studies are mainly focused on soil properties, vegetation or soil microbiology separately; studies which consider all of these components are limited. This paper attempted to apply the perspective of systemic theory to provide scientific evidence for grassland degradation. Various degraded grasslands, located at the northeast margin of Qinghai-Tibetan Plateau, were selected for the study. Grassland characteristics were identified and associations between vegetation and soil microorganism properties were investigated using correlation analysis. The results showed that the number of plant species reduced with increased degradation and the dominant species changed.Additionally the height, coverage and aboveground biomass of the plant community decreased significantly (P<0.05) with enhanced degradation. Soil microbial carbon and nitrogen content also decreased with enhanced degradation. Aboveground biomass decreases by 88.6% from lightly degraded grassland (LDG) to severe degraded grassland (SDG). The microbial biomass of carbon (218.90 mg/kg) and nitrogen (44.32 mg/kg) in LDG were significantly higher than those in SDG (P<0.05), but there was no difference between moderate degraded grassland (MDG) and SDG. Soil microbial quotient was not affected by degradation. There was a significant positive correlation between aboveground biomass and microbial biomass (P<0.05).
    Effects of Haloxylon ammodendron planting on soil physico-chemical properties and soil microorganisms in sandy dunes
    XI Jun-Qiang, YANG Zi-Hui, GUO Shu-Jiang, WANG Qiang-Qiang, ZHANG Jian-Hui, WANG Duo-Ze
    2015, 24(5):  44-52.  DOI: 10.11686/cyxb20150506
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    In this research, the soil microbe populations, soil physical and chemical properties, and the correlation between microbe populations and soil properties of a 20-year old Haloxylon ammodendron plantation in sandy dunes and moving sandy dunes in Minqin were studied. The research aimed to explore the influence of H. ammodendron planting on soil formation on sand dunes and provide a scientific basis for desert land management in arid areas. The results showed that soil in the H. ammodendron plantation was much improved. Soil clay, silt and fine sand contents were increased 71.51%, 70.64%and 12.09%, respectively, compared to nearby unplanted areas. The contents of organic matter, total nitrogen, total phosphorus, total potassium, hydrolytic nitrogen, potassium, available phosphorus and CaCO3 were increased as well. In addition, the quantities of bacteria and actinomycetes were increased by 38.43% and 32.52%, respectively, while presence of fungi was decreased by 75.38%. Soil alkalinity was also reduced. Soil moisture contents were reduced which can be attributed to transpiration withdrawal of water by H. ammodendron in the 50-100 cm soil depth. Soil microbe populations were highly correlated with soil physical and chemical properties, especially fungi and actinomycetes, which showed a strong negative correlation with pH value (P<0.05); and soil organic matter level displayed an obvious positive correlation with numbers of bacteria and fungi (P<0.05). Soil microbe quantities have a linear relationship with soil particle size and soil moisture content but without significance (P>0.05). In summary, H. ammodendron plantating improves soil physical structure, increases soil fertility and accelerates the process of soil formation.
    Effect of Citrus tree/Stropharia mushrooms intercropping on “purple soil” labile organic carbon in the Three Gorges Reservoir region
    ZHANG Yang, LIU Yue-Jiao, NI Jiu-Pai, XIE De-Ti
    2015, 24(5):  53-65.  DOI: 10.11686/cyxb20150507
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    In order to provide basic data and a theoretical basis for soil carbon cycle and climate change mitigation research, the effect of Citrus tree/Stropharia mushrooms intercropping on “purple soil” labile organic carbon was analyzed. Five tillage practices: high density intercropping (HD), traditional cultivation (TC), sparse intercropping (SP), bare ground tillage (BT) and straw mulching tillage (ST) were examined to analyze the soil total organic carbon (TOC), dissolved organic carbon (DOC), rapidly oxidized organic carbon (ROC), light fraction organic carbon (LFOC) and soil microbial biomass carbon (SMBC) in citrus groves. During the growing season of Stropharia mushrooms, the density of Citrus tree/Stropharia mushrooms intercropping significantly affected the labile carbon (including DOC, ROC, LFOC, SMBC). As expected, the content of total organic carbon and labile carbon in the upper layer (0-10 cm soil depth) was significantly higher than in the lower layer (30-50 cm soil depth). The content of labile carbon (including DOC, ROC, LFOC, SMBC) in the upper soil layer under high density intercropping (HD) practice was significantly higher than under the other treatments (P<0.05), while the contents of dissolved organic carbon (DOC), light fraction organic carbon (LFOC) and soil microbial biomass carbon (SMBC) in lower soil layer under sparse intercropping (SP) were higher than under the other treatments. Intercropping density was significantly negatively correlated with total organic carbon (TOC) and rapidly oxidized organic carbon (ROC). There was a significant negative correlation between the intercropping density and dissolved organic carbon (DOC), light fraction organic carbon (LFOC) and soil microbial biomass carbon (SMBC). In addition, there was a significant positive correlation among different fractions of labile carbon. Citrus tree/Stropharia mushrooms intercropping enhanced the soil carbon pool management index in the upper soil layer, but decreased the same index in the lower soil layer. Citrus tree/Stropharia mushrooms intercropping enhanced formation and accumulation of soil labile carbon and increased soil carbon storage in this soil type in the Three Gorges Reservoir region.
    Soil characteristics of medlar wood growing on secondary salinization land in Jingdian irrigation zone
    LI Yin-Ke, MA Quan-Lin, WANG Yao-Lin, SUN Tao, JIN Hu-Jia, SONG De-Wei, ZHU Guo-Qing, DU Juan
    2015, 24(5):  66-74.  DOI: 10.11686/cyxb20150508
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    This study evaluates the effect of planting medlar on the sustainable use of secondary salinized land. The physical and chemical properties of secondary salinized soil were investigated under different land use patterns, including an abandoned field (AF), medlar fields with different planting years (MF) and a wheat field (WF). Compared to AF, the MF soils showed significant increases in organic matter, total nitrogen, available nitrogen, and HCO3-, while total salt content and electrical conductivity significantly decreased. The most significant decrease was in Na+ (70.1%-82.9%). Results also showed that in MF soils the sand content decreased and silt and clay content increased. CaCO3 content increased and pH value decreased. However, bulk density firstly decreased and then increased over time, while porosity showed an opposite trend when compared with AF. K+ and total salt content were higher in MF than in WF by 118.1%-282.3% and 84.0%-211.5% respectively. Other soil physical and chemical properties showed no significant differences between MF and WF. The results show that secondary salinized soil quality is improved by planting medlar. Although Na+ content was significantly higher, other soil characteristics were relatively low compared to salinization of traditional cropland. The improvement of soil characteristics was rapid during the first 4 years of medlar planting and then slowed considerably. The study thus shows that changes in land use patterns greatly influence the soil characteristics of secondary salinized land.
    Effects of water and fertilizer on growth and photosynthetic pigments of Puelia sinense
    ZHANG Ming-Jin, CHEN Liang-Hua, Hu Xiang-Wei, Xu Rui, ZHANG Jian
    2015, 24(5):  75-83.  DOI: 10.11686/cyxb20150509
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    A pot experiment was conducted to detect the interaction effect of water and fertilizer on growth and photosynthetic pigments of Puelia sinense. The experiment was a completely randomized design with 9 factorial combinations of 3 levels of water [drought, 25% field capacity (FC); control, 75% FC; flooding, 100% FC)] and fertilizer (low, moderate, high levels of fertilizer). Above-ground biomass, below-ground biomass, total biomass, and root: shoot ratio were significantly affected by the interaction of water and fertilizer. For the control water treatment, a high level of fertilization led to increased tiller number and plant height, and greater below-ground, above-ground, and total plant biomass. This combination was the best among the 9 combinations. These results indicate that normal supply of water and high nutrient supply are the optimal conditions to achieve a high yield for this species. Both flooding and drought were detrimental to tillering and growth. However, under water deficit where a tillering reduction was observed, tillering capacity could be improved through fertilization. Under flooding, high fertilization was not beneficial and a moderate amount of fertilizer was sufficient for optimal accumulation of below-ground biomass. Plants in these conditions had a higher root to shoot ratio, possibly a plant response to hypoxic conditions. Compared to flooding, drought was more detrimental to the accumulation of above-ground biomass. In order to adapt to drought, P. sinense allocated more assimilate to the belowground organs. The increased root: shoot ratio was presumably advantageous for plant water capture and so to adaptation to drought. Interestingly, under water deficit stress, concentrations of photosynthetic pigments were significantly higher than those under control conditions. With increase in fertilization, contents of photosynthetic pigments also increased, especially when exposed to drought at the same time. These results elucidated some morphological and physiological adaptive mechanisms of this species when responding to water-deficit. Increased fertilization could mitigate the detrimental effects of water deficit stress on plant growth to some degree.
    Effect of waterlogging on antioxidant and anaerobic respiratory enzymesin Medicago sativa varieties from southern and northern China
    QUAN Rui-Lan, YU Yong-Xiong
    2015, 24(5):  84-90.  DOI: 10.11686/cyxb20150510
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    Two Medicago sativa varieties, Yumu No.1 (southern China) and Xinjiangziniquan (northern China), were compared. Six waterlogging treatments; 0, 2, 4, 6, 8 and 10 days of waterlogging were imposed on seedlings at the 4-leaf stage. The malondialdehyde (MDA) content, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity in the leaves and lactate dehydrogenase (LDH), pyruvate (PDC) and alcohol dehydrogenase (ADH) activity in the roots were evaluated in all treatments. Biomass was measured after 10 days of waterlogging. Waterlogging stress reduced the biomass of both varieties but Yumu No.1 was less affected than Xinjiangziniquan. The activities of SOD, POD and CAT in leaves of Yumu No.1 were higher than those of Xinjiangziniquan under waterlogging stress, but the MDA content in the leaves was lower than that of Xinjiangziniquan. The activity of respiratory enzymes in the roots was influenced by waterlogging; In Yumu No.1 ADH and PDC activity increased more than LDH activity with stronger alcohol dehydrogenaseactivity, while in Xinjiangziniquanwaterlogging resulted in increased LDH and lactic dehydrogenase activity. It was concluded that the greater tolerance of waterlogging observed in Yumu No.1 was primarily due to higher antioxidant enzyme and anaerobic respiratory enzyme activity.
    Effects of NaCl stress on substances linked to osmotic adjustment and on photosynthetic physiology of Melilotoides ruthenica in the seedling stage
    YAO Jia, LIU Xin-Bao, CUI Xin, LI Zhi-Hua
    2015, 24(5):  91-99.  DOI: 10.11686/cyxb20150511
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    The effects of various levels of NaCl stress [0 (control), 50, 100, 150, 200, 250, 300 mmol/L] on the osmotic adjustment matters and photosynthetic physiology of Melilotoides ruthenica seedlings were investigated in pot experiments. Soluble protein and sugar contents of seedlings decreased with increasing NaCl concentration. However, proline content increased with increased NaCl concentration. The contents of soluble protein, sugars, and proline differed under different salt concentrations and stress exposure times. On the 7th day and 14th day after imposing stress, soluble protein contents of seedlings exposed to 300 mmol/L NaCl concentrations were significantly lower than those of controls (P<0.05). On the 7th, 14th and 21st day after imposing stress, soluble sugar contents of seedlings exposed to 50 or 100 mmol/L NaCl concentration were higher than those of the controls, while on 28th day after stress, soluble sugar contents of seedlings exposed to 250 or 300 mmol/L NaCl concentrations were significantly lower than those of the controls (P<0.05). On the 7th day after imposing stress (150-300 mmol/L NaCl), the 14th day after imposing stress (200-300 mmol/L NaCl) and on the 28th day after imposing stress (250 or 300 mmol/L NaCl), the proline content was significantly higher than that of the control and other treatments (P<0.05). Hence under salt stress, three indicators of osmotic adjustment had different time signatures. With increases in both NaCl concentration and stress exposure time, the physical damage to M. ruthenica seedlings became more serious, while photosynthetic parameters varied with NaCl concentration and stress exposure time. On the 14th day after imposing stress, photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and intercellular CO2 concentration (Ci) increased at low, and decreased at high salt concentration. Pn, Tr, and Gs of seedlings under 50-100 mmol/L concentrations were significantly higher than those of control plants, while Pn and Tr of seedlings under 300 mmol/L were significantly lower than those of control plants and of other treatments (P<0.05). On 28th day after imposing stress, Pn, Tr, Gs and Ci were decreased with increasing of salt concentrations. On the 14th and 28th days after imposing stress, stomatal limitation (Ls) and water use efficiency (WUE) increased with increasing NaCl concentration.
    Effects of Cd2+ on the seed germination and seedling growth of Cynodon dactylon and Eremochloa ophiuroides
    QIN Hua-Meng, PENG Ling-Li, YANG Xue, WU Ya-Jiao, LIAO Yuan-Lin, LI Xi, CHEN Qi-Bing, CAI Shi-Zhen
    2015, 24(5):  100-107.  DOI: 10.11686/cyxb20150512
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    The effect of Cd2+ concentration on the germination and growth of Cynodon dactylon and Eremochloa ophiuroides has been studied. The results showed that the seed germination rate, germination vigor, germination index, vigor index, root length and seedling length of the two turfgrass species decreased with increases in Cd2+ concentration. Chlorophyll content in leaves decreased slightly and the MDA contents in leaves showed a rising trend after an initial drop with increasing Cd2+ concentration. The CAT activities of C. dactylon increased at first and then decreased with increasing concentrations. At a Cd2+ concentration of 5.0 mg/L, CAT activities were significantly higher than that of CK, while the CAT activities of E. ophiuroides in all treatments were lower than that of CK. The POD activities of the two turfgrass species increased at first and then decreased with increasing Cd2+ concentration, reaching its peak at 10.0 mg/L. The PPO activities of C. dactylon and E. ophiuroides were higher than CK when the concentrations were at 5.0, 10.0, 20.0 and 40.0 mg/L. With increasing Cd2+ concentrations, the PPO activities of both species showed a declining trend following an initial rise. The two turfgrass species have a certain degree tolerance of Cd2+, with the tolerance of C. dactylon greater than that of E. ophiuroides. Both turfgrass species can thus be used in soils with low levels of Cd2+ pollution.
    Effects of exogenous silicon on melon seed germination and the growth of seedlings under NaCl stress
    WANG Yu-Ping, WANG Ying-Xia, BAI Xiang-Li, WANG Xiao-Qing, ZHANG Feng
    2015, 24(5):  108-116.  DOI: 10.11686/cyxb20150513
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    The effects of exogenous silicon on the growth of melon under salt stress were investigated. Seedlings of two melon cultivars (Xueli No.1 and Longqinyinmi) with different salt tolerance were grown with 125 mmol/L NaCl stress Exposure to 125 mmol/L NaCl stress significantly inhibited melon seed germination. Compared with control, treatments with 0.5-1.0 mmol/L exogenous silicon significantly increased seed germination rate, germination energy, germination index, alpha-amylase activity and water absorption and the treatment with 0.75 mmol/L exogenous silicon performed best. In addition, melon seedlings with 0.25-1.00 mmol/L silicon exposed to 125 mmol/L NaCl had significantly increased plant height, leaf area, chlorophyll content, shoot dry weight and root dry weight, compared to controls. Treatment with 0.50 mmol/L was optimal for Longqinyinmi, while 0.75 mmol/L gave best results for Xueli No.1. These results indicate that exogenous silicon concentration from 0.50 mmol/L to 0.75 mmol/L can promote melon seed germination by enhancing alpha-amylase activity and water absorption, and promote seedling growth by increasing chlorophyll content and photosynthesis capacity under salt stress. When the silicon concentration was more than 1.25 mmol/L, there was no effect on the seed germination and growth of seedlings under salt stress.
    Analysis of the nutritional components and feeding values of commonly used roughages
    CHEN Yan, WANG Zhi-Sheng, ZHANG Xiao-Ming, WU Fa-Li, ZOU Hua-Wei
    2015, 24(5):  117-125.  DOI: 10.11686/cyxb20150514
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    The nutrient composition of different roughages was evaluated using basic chemical analysis and the Cornell net carbohydrate and protein system (CNCPS). Nutrient composition was compared and feeding values calculated using the prediction formula for feeding quality evaluation. The results indicated that the contents of crude protein (CP), ether extract (EE), soluble crude protein (SCP), and non-protein nitrogen (NPN) in Lolium perenne, Hemarthria altissima and sweet potato stem were significantly higher than those in corn stover and rice straw. In contrast, contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) in L. perenne, H. altissima and sweet potato stem were significantly lower than those in corn stover and rice straw. The L. perenne and sweet potato stem had higher levels of sugar (CA) and rapidly degraded pure protein (PB1) than the other roughages analyzed. Compared to corn stover and rice straw, H. altissima, L. perenne and sweet potato stem had higher levels of starch, pectin (CB1), non-structural carbohydrates (NSC) and slowly degraded pure protein (PB3). Rice straw had the highest levels of available fiber (CB2), and corn stover had the highest levels of carbohydrate (CHO), unavailable fiber (CC) and intermediately degraded pure protein (PB2). The amino acid (AA) components of the roughages were significantly different, with different potentials for supplying limiting amino acid (LAA). Among the roughages analyzed, L. perenne had the highest level of total amino acids (TAA), essential amino-acid (EAA) and LAA, while corn stover and rice straw had the lowest. L. perenne had higher levels of digestible dry matter (DDM) and relative feed value (RFV) than the other roughages. The contents of dry matter intake (DMI) and RFV in sweet potato stem were significantly higher than those in H. altissima, while the contents of DMI, DDM and RFV in corn stover and rice straw were the lowest levels, with no significant differences between them. Therefore, L. perenne has the highest nutrient value and H. altissima and sweet potato stem are mid-range, while corn stover and rice straw have the lowest nutrient value.
    Effects of wilting and additives on fermentation quality of alfalfa (Medicago sativa) silage
    LIU Hui, BU Deng-Pan, LV Zhong-Wang, LI Fa-Di, LIU Shi-Jie, ZHANG Kai-Zhan, WANG Jia-Qi
    2015, 24(5):  126-133.  DOI: 10.11686/cyxb20150515
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    The effect of wilting and different additives on alfalfa silage fermentation and nutritive value were studied under laboratory conditions. Alfalfa (at the early bloom stage of maturity), wilting 3 and 12 h respectively, was ensiled at 72.6% and 61.8% moisture content either untreated (CK) or treated with inoculant (LAB), sugar beet pulp (SB), inoculant and sugar beet pulp (LAB+SB), sodium formate (SF) and the combination of sodium formate and sugar beet pulp (SF+SB). Silo was opened and analysed after 65 d of ensiling. The results showed that additives addition generally had an significantly effect on alfalfa silage characteristics in terms of lower pH and ammonia-N concentration (P<0.01). Treated silage had a similar concentration of neutral detergent fiber (NDF), acid detergent fiber (ADF) and dry matter recovery compared with untreated silage. The addition of sugar beet pulp (SB) greatly reduced crude protein concentrations (P<0.05). Water-soluble carbohydrate concentrations were found increased in silage from alfalfa herbage treated with inoculant and sugar beet pulp combined and sodium formate prior to ensiling (P<0.05). As silage wilting enhanced, silage quality was improved. In general, different additives had different effect on ensiling. Inoculant and sugar beet pulp combined (LAB+SB) was found to be the most effective additive.
    Construction of a genetic map for chicory usingsequence-related amplified polymorphism markers
    LIANG Xiao-Yu, JI Yang, BAI Shi-Qie, HUANG Lin-Kai, ZHANG Xin-Quan
    2015, 24(5):  153-158.  DOI: 10.11686/cyxb20150518
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    Sequence-related amplified polymorphism (SRAP) markers were used to construct a draft linkage map using an F1 population (84 individual plants) derived from a cross between PI 651947 and PI 652007; these lines possess different agronomic traits and DAN levels. Draft linkage maps of PI 651947 and PI 652007 were constructed using Map Manager QTX b20 software. 77 markers were used to construct parental linkage maps.The male map included 4 linkage groups with 19 molecular markers covering a total length of 450.9 centimorgans (cM). The average genetic distance between markers was 23.7 cM. The female map included 13 linkage groups with 58 molecular markers and covered a total length of 1404.8 cM. The average genetic distance between markers was 24.2 cM. This information established a foundation for extending genetic mapping in chicory and will serve as a framework for mapping QTLs and provide information required for further molecular studies.
    Comparison of four glyphosate tolerance genes
    LIU Jian, XIAO Ya-Wen, LU Jia, WU Zhong-Yi, ZHANG Zhong-Bao, XU Jie, YAO Lei
    2015, 24(5):  159-166.  DOI: 10.11686/cyxb20150519
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    Glyphosate tolerance is an important agronomic trait in modern agriculture. In order to determine the best glyphosate tolerance gene for plant selectable markers we compared four glyphosate tolerance genes, cp4-epsps, GR79-epsps, gat4621 and GAT, in Arabidopsis. Four transgenic plants harboring each gene were treated with four different rates of glyphosate. The results showed that the resistance of plants with GAT gene was significantly higher than plants with the epsps gene. Plants with the gat4621 gene had the highest survival rate at all herbicide rates. The plants with the domestic GAT gene also had strong resistance. Reproductive development of Arabidopsis plants with the GAT gene was suppressed at higher glyphosate application rates.It was concluded that the GAT gene was more suitable as a selectable marker gene.
    Floral sex allocation and gynomonoecy of Ligularia (Asteraceae) in the eastern Qinghai-Tibet Plateau
    XIE Tian-Peng, DU Guo-Zhen, BU Hai-Yan
    2015, 24(5):  167-174.  DOI: 10.11686/cyxb20150520
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    Gynomonoecy is the sexual system in which female and bisexual flowers occur on the same plant. Little attention has been paid to the adaptive significance of this sexual system. In this paper, we investigated 3 common species of the genus Ligularia (Asteraceae) in the eastern part of the Tibetan Plateau and examined the effects of flower head position, plant height and leaf removal on floral sex allocation. The results showed that plants of these three Ligularia genera were self-incompatible, and the intra-inflorescence variations in floral traits were significant. Regardless of whether the racemes developed from top to bottom or in the opposite direction, the early-formed flowers within a raceme were larger and displayed female-biased sex allocation. The later-formed flowers had more ovules and displayed a male-biased sex allocation. Taller plants have a lager flower display and invest more resources in the female state. Raceme size and investment in ray floret biomass were significantly decreased in plants with leaves removed. However, plant height and leaf removal did not change the variation of floral traits within inflorescences. The adaptive significance of gynomonoecy in Ligularia lies in permitting flexibility in allocation of resources to male and female functions. Ecologically this behavior may link seed set to resource availability and may assist with attracting pollinators, and may also reduce conflict between male and female functions.
    Leaf morphology and numerical taxonomy of 4 genera of the tribe Galegeae in northeastern China
    SHI Chuan-Qi, LIU Mei, WANG Chen
    2015, 24(5):  182-189.  DOI: 10.11686/cyxb20150522
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    The leaf morphological structure of 25 species,representing 4 genera from the tribe Galegeae, northeastern China, was determined using GMA, SEM and leaf transparency methods. Twenty-three morphological features related to leaf and 8 non-leaf characters were selected for cluster analysis and principal component analysis. Three groups were identified; Astragalus and Gueldenstaedtia were placed in one group, and Glycyrrhiza and Oxytropis in separate groups. Features including the presence of glands, petiole shape and tannin content of petiole cells were able to distinguish Glycyrrhiza pallidiflora and G. uralensis from other Galegeae species. Stipule texture, connectivity between stipule and petiole and leaflet margin features are all useful identification characteristics of Oxytropis. Stipule shape is valuable for interspecific classification. This study provided the leaf morphological evidences for taxonomy of the Galegeae and Leguminosae systematics.
    Morphological and anatomical features of Lamiaceae fruits in northeasten China and notes on taxonomic value
    RU Jian, LIU Mei, WANG Chen, CHENG Xin-Yu, LIANG Li
    2015, 24(5):  190-205.  DOI: 10.11686/cyxb20150523
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    The fruit structures of 52 species and 5 varieties representing 26 genera from 4 subfamilies of Lamiaceae in northeasten China were deeply studied in the paper for the first time, using glycol methacrylate(GMA) sections and cells of the sclerenchyma region were separated for identifying the structure. The results show that the fruits of the family are mainly trigonous in shape, sometimes the edges of the fruits extend and form wing. The fruit surfaces are glabrous, reticulate or with hairs (including capitate or peltate glandular hairs, unicellular, uniseriate multicellular or branched non-glandular hairs). The areola of the fruit is mainly round, barely linear or V-shape. The pericarp could be divided into four parts: exocarp, mesocarp, sclerenchyma region and endocarp. The crystal exists in the sclerenchymatous region. The study completes the fruit anatomy of Lamiaceae in northeasten China and provides the basis for the further research of the fruit anatomy and taxonomy, and molecular systematics of Lamiaceae in China.
    Review of methodology and factors influencing plant root respiration
    DING Jie-Ping, LUO Yong-Qing, ZHOU Xin, YUE Xiang-Fei, LIAN Jie
    2015, 24(5):  206-216.  DOI: 10.11686/cyxb20150524
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    Plant root respiration is the dominant component of total soil respiration, which in turn is closely related to the carbon cycle of terrestrial ecosystems and a significant factor in global climate change. Research focused on plant root respiration is critical for understanding ecosystem carbon budgets and the biosphere’s carbon balance. Root respiration is affected by both environmental and biotic factors. Root respiration rates and their contribution to soil respiration varies greatly in different ecosystems. The main methodologies in research on root respiration include direct measurement (such as isolated methods/in vitro root methods, isotopic methods and cuvette methods) and indirect methods (such as the root exclusion method and calculation method). Plant root respiration is affected by soil temperature and humidity, nutrition condition and root size, root order, root biomass and root mycorrhiza. This paper reviews the various methodologies and factors held to influence plant root respiration in order to provide the basic theory needed for subsequent research. Future research directions are also suggested.
    Dynamic simulation of landscape change using VDDT in Hongyuan County
    ZHANG Xue-Lian, GAN Xiao-Yu, DAO Li-Gang, ZHANG Hong-Xuan, DONG Kui, YOU Cheng-Ming, FU Pei-Bin, GAN You-Min
    2015, 24(5):  217-223.  DOI: 10.11686/cyxb20150525
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    Based on remote sensing images of Hongyuan County collected between 2000 and 2010, a landscape classification map and grassland resource database were produced using ENVI software. In addition, 9 disturbance types were chosen to simulate the landscape succession to the year 2020 using the United States department of Agriculture Vegetation Dynamics Development (VDDT) tool based on the transition probability for 2000-2001. The results showed that: 1) In the 20 years, grassland decreased by about 824 km2, and forest by 191 km2, however, the unutilized area was predicted to increase by about 89 km2; 2) The VDDT tool provided an acceptable simulation of the landscape succession as indicated by the Hongyuan County land use maps for 2000 and 2010 [R2=0.9325(Area), R2=0.8833(Number)]; 3) The simulation showed an obvious degeneration trend for grassland in Hongyuan county. Factors affecting the future landscape pattern and rate of grassland degeneration were also analyzed.
    Effect of burrow entrance densities of plateau pika (Ochotona curzoniae) on interspecific association in Kobresia pygmaea meadow
    PANG Xiao-Pan, WANG Qian, JIA Ting-Ting, LI Qian-Qian, GUO Zheng-Gang
    2015, 24(5):  224-230.  DOI: 10.11686/cyxb20150526
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    Changes in the active burrow entrance densities of plateau pika (Ochotona curzoniae) can result in changes in the botanical composition in Kobresia pygmaea meadow which can influence interspecific relationships in the meadow. A field survey was carried out to determine the effect of active plateau pika active burrow entrance densities on the interspecific association between the major plant species in K. pygmaea meadow. This study showed that the dominance index for K. pygmaea (dominant species), decreased, while the dominance index of associated species including Gentiana dahurica and Anemone rivularis var. flore-minors increased as burrow density increased. The overall interspecific association among the main plant species of the K. pygmaea alpine meadow transformed from significantly positive association at 128 and 224 burrow entrances per ha to a negative association at 368 and 544 burrow entrances per ha. The relationship between K. pygmaea and Carex moorcroftii transformed from positive association at 128 and 224 active burrow entrances per ha to negative association at 368 and 544 active burrow entrances per ha, while associations between Euphorbia esula and Elsholtzia densa, and between Oxytropis ochrocephala and E. esula were negative at 128 and 224 active burrow entrances per ha but positive at 368 and 544 burrow entrances per ha. These results suggested that the active burrow entrance densities regulated the overall interspecific association among the main plant species in K. pygmaea alpine meadow, and the interspecific association among the main plant species was strongest and the stability of the alpine meadow community was greatest at 224 active burrow entrances per ha.