Table of Content

20 August 2014, Volume 23 Issue 4

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Orginal Article

Dynamic changes of grassland vegetation coverage from 2001 to 2011 in Gannan Prefecture

MA Lin-ya,CUI Xia,FENG Qi-sheng,LIANG Tian-gang

2014, 23(4):  1-9.  DOI: 10.11686/cyxb20140401

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Vegetation coverage is an important indicator of grassland vegetation growth condition,and it has a crucial significance for evaluation and analysis of vegetation restoration. Using the Terra/MODIS product of MOD13A3 from May to October during 2001-2011,combined with ground observed data from 2006-2009,the inversion models of grassland vegetation coverage were established. Their precisions were compared and the characteristics of grassland vegetation coverage in the growing seasons of 2001-2011 were analyzed in Gannan Prefecture. The logarithmic function (y=33.658ln x+112.65) of MODIS-EVI (enhanced vegetation index) best simulated grassland vegetation coverage in Gannan pastoral areas with aprecision of 93.31%. MODIS-EVI had more advantages in high vegetation coverage regions,and accurately reflected the spatial and temporal differences of vegetation coverage while reducing the effect of environmental factors to the maximum extent. In the recent 11 years,grassland vegetation coverage in Gannan Prefecture has shown an increasing trend. The grassland vegetation coverage was highest (78.43%) in 2005,and the vegetation coverage of 2001,2003,and 2008 were lower than those in other years. The vegetation coverage in mid-west and southwest areas was better than that in the eastern area. Grassland vegetation was dominated by high,then higher vegetation coverage levels,while the proportion of other grassland vegetation coverage levels were small (6.98%) and stable. Overall,grassland in Gannan Prefecture for the 11 years was characterized by transformation from a high vegetation coverage into an even higher vegetation coverage.

Community characteristics of Stipa purpurea stepp in the Qinghai Lake region

YUE Peng-peng,LU Xue-feng,YE Run-rong,ZHOU Yu-bi,YANG Shi-bing,PENG Min

2014, 23(4):  10-10.  DOI: 10.11686/cyxb20140402

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The classification,association and distribution characteristics and relationships between the distributions and environmental factors of Stipa purpurea steppe in the Qinghai Lake region were studied. A combined transect and quadrat method was used to collect field data. Multivariate statistical methods,including cluster analysis,TWINSPAN (two-way indicator species analysis),DCA (detrended correspondence analysis),CCA (canonical correspondence analysis) and correlation analysis,were used to calculate the data on the basis of investigating a large number of vegetation communities in this region. The species composition of S. purpurea in the study area was relatively simple. The dominant families of seed plants were Gramineae and Compositae,and the dominant aerial types of genera were North temperate types. The community in the area could be classified into 4 associations: Ass. S. purpurea+Astragalus polycladus,Ass. S. purpurea+Kobresia humilis,Ass. S. purpurea+Poa indattenuata,Ass. S. purpurea+Sinochasea krylovii. The major environmental factors influencing the distribution of steppe types in the area were first climate factors (mainly average annual precipitation and temperature),then soil factors (mainly soil moisture,organic matter and N,P,K). Changes in evenness index and Simpson index of S. purpurea stepp associations were basically the same,and the indexes of Ass. S. purpurea+Poa indattenuata were the highest. Richness index was largely affected by climate and soil factors,but the Simpson index and evenness index of all environmental factors investigated were not significantly correlated with area. The present study provides the ecological parameters of S. purpurea steppe in the Qinghai Lake region and would be a basis for maintaining the ecosystem equilibrium of ecologically fragile zones.

Research on responses of Eupatorium adenophorum’s potential distribution to climate change

WANG Chong,LIN Hui-long,HE Lan,CAO Ao-cheng

2014, 23(4):  20-30.  DOI: 10.11686/cyxb20140403

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Eupatorium adenophorum is one of the most invasive alien species in China. It has a strong ecological adaptability,and it can seize the niche very quickly thus the native species would be posed a threat to biodiversity by being crowded out. In order to study the potential distribution of E. adenophorum and its response to climate change,also to find out the environmental factors which influence the distribution of E. adenophorum,the ecological niche factor analysis (ENFA) and the maximum entropy model were combined in this study. Firstly the environmental factors dimension was reduced by ENFA; secondly together with current and future climate data the study use MaxEnt model to predict the distribution of E. adenophorum in the future. The results showed that in the A1b scenario,the main distribution areas were Yunnan,Guizhou,and Guangxi province. From now to 2080s,the area of L₄₅ grade (the invasion probability is 0.6-1.0) was increased from 12.82 km² of nowadays to 21.30 km² in 2080s,and the center moved 46.62 km northwest. While the area of L₅ grade (the invasion probability is 0.8-1.0) was increased from 0.42 km² of nowadays to 0.91 km² in 2080s,and the center moved 178.66 km northeast. According to the research of the potential distribution of E. adenophorum in the current and future,the area of different invasion grade could be controlled by appropriate measures,and it will provide an important guidance for the comprehensive management.

Analysis of growth characteristics, nutritional components and feeding values of native forage grass from the high-cold steppes in the Luqu and Hezuo region of Gannan in summer and winter

WU Fa-li,WANG Zhi-sheng,YANG Qin,SHI Hong-mei,SHEN Jun-hua,HU Rui,ZOU Hua-wei

2014, 23(4):  31-38.  DOI: 10.11686/cyxb20140404

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The growth characteristics,nutritional components and feeding value of the native forage grass from high-cold steppes (Luqu and Hezuo region of Gannan) in winter and summer were studied using four kinds of forage grass for chemical analysis and prediction models were made of forage quality evaluation in a comparison experimental design. Treatments were: forage grass from Luqu in summer (LQX),from Luqu in winter (LQD),from Hezuo in summer (HZX),and from Hezuo in winter (HZD). Compared with winter,forage grass from the two regions in summer (HZX,LQX) had higher crude protein,total phosphorus (TP),dry matter intake (DMI),digestible dry matter,relative feed value (RFV),organic matter digestibility and fresh forage yield (P<0.05). However,they were lower in crude fibre,neutral detergent fiber,acid detergent fiber,and the ratio of Ca/TP than that in winter (HZD,LQD) (P<0.05). In winter,the ratio of Ca/TP and acid detergent lignin in the forage grass from Luqu (LQD,LQX) was lower than that from Hezuo (HZD,HZX) (P<0.05) and the forage grass from Hezuo (HZD) had lower hemicellulose HC and amount of nitrogen free extract than other kinds of forage grass (P<0.05). In summer,DMI and RFV of the forage grass from Hezuo (HZX) were significantly higher than those from Luqu (LQX) (P<0.05). Growth characteristics,nutritional components,and feeding value of the forage grass from Gannan in summer were better than that in winter,and the forage grass from Luqu was better than that from Hezuo in high-cold steppes (Gannan region).

Comparison of the production performance of ryegrass cultivars and screening of dominant varieties

LIU Chun-ying,SUN Xue-ying,ZHU Ti-chao,CHEN Guang-rong,ZHENG Zhang-yun

2014, 23(4):  39-48.  DOI: 10.11686/cyxb20140405

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The production performance of nine different ryegrass cultivars were investigated to screen for the dominant varieties using a field variety test. The production performances were compared and evaluated by variance analysis,grey correlation analysis and Hierachical clustering analysis of ten traits. The production performances differed on the basis of different cutting times or growth stages: the 2nd cutting of ryegrass had faster growth and development with higher yields and quality. The best growth period of ryegrass for green-feed and silage is from February to May. The production performance of the different cultivars was also related to genetic differences. Fresh/hay yield ratios,tillers,stem/leaf ratios,crude protein content and growth intensity of Diploid,Tetragold and Calibrawere better than those of the control (Abundat).These three species were ranked in the top three places using grey correlation degree analysis and were clustered into one group using Hierachical clustering analysis. Their comprehensive characteristics performed well,therefore they could be used as dominant forage species with a good prospect for popularization and application in Wanzhou. Ellett had a lower weighted incidence degree but higher tiller and ratio of dry matter than the others,and it was the only one in its group,so it could be used as a special breeding material. The others all clustered into the same group and had a comprehensive performance equivalent to that of the control so that they could be appropriately planted in similar situations.

Constructing pre-core collection of Cynodon dactylon based on phenotypic data

ZHENG Yi-qi,GUO Yan,FANG Shu-juan,XU Ya-nan,CHEN Jing-bo,LIU Jian-xiu

2014, 23(4):  49-60.  DOI: 10.11686/cyxb20140406

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In this study,the method of constructing Cynodon dactylon pre-core collection was studied based on 15 quantitative and qualitative traits from 831 accessions. An optimal sampling scheme was selected from 48 strategies which consisted of sampling proportions (5%,10%,15%,20%,25%,and 30%),sampling proportions within group (simple proportion,logarithmic proportion,square root proportion and genetic proportion) and individual selection methods within group (random selection and cluster selection) evaluating with four effective parameters including mean difference percentage,variance difference percentage,coincidence rate of range and changeable rate of variation coefficient. The optimal sampling scheme was also confirmed by comparing the accessions distribution plotted by first two principal components,correlation coefficients of traits between two collections. The result indicated that 25% was the optimum sampling proportions. The square root proportion was better than simple proportion,logarithmic proportion and genetic proportion. The cluster selection was more suitable than random selection. At 25% sampling proportion,using square root proportion within group and cluster selection method within group is the most suitable method for constructing C. dactylon pre-core collection. The result conducted by PCA analysis showed the genetic structure and variation of 831 accessions was well represented by the pre-core collection. The most important phenotypic correlations between traits which may be under the control of co-adapted gene complexes were also preserved by the pre-core collection. Based on the optimized sampling strategy,the pre-core collection consisting 208 accessions of C. dactylon were established and will play an important role in the utilization of C. dactylon genetic resources.

The effect of different super absorbent polymer applying layer on turf growth and soil water and fertility

LI Jia-ling,LI Long-bao,LIAO Zong-wen,LIU Tian-zeng,ZHANG Ju-ming

2014, 23(4):  61-67.  DOI: 10.11686/cyxb20140407

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The study was conducted to research best layer which can be applied super absorbent polymer for increasing usage rate of water and fertilizer in perennial ryegrass turf medium. The treatment was applying SAP 5 cm under the soil horizon,10 cm under the soil horizon,15 cm under the soil horizon and blank control respectively. It adopted two different watering methods: normal irrigation and large leaching irrigation,and then we tested and analyzed turfgrass growth rate,soil water content,amount of leaching nutrient,change of soil nutrient and perennial ryegrass turfgrass apparent traits at regular intervals. The study illustrated that 20 cm deep and 7.5 cm shallow applied layer had different effects on soil water content,the capacity of retaining fertilizer,turf density,and SAP can improve the capacity of retaining fertilizer and play a role in water retention in perennial ryegrass turfgrass in different layers. Applying SAP at 5 cm under the soil horizon was considered the best layer in turf medium as this depth had the best capacity of water,N and P retention,as well as producing the maximum turf density.

Relationship between grain filling and accumulation and remobilization of water soluble carbohydrates in leaf and stem of winter wheat during the grain filling in different water conditions

MA Zhao-peng,LI Meng-fei,YANG De-long,CHEN Xiao-ping,CHEN Jing-jing,LIU Yuan,LI Wei

2014, 23(4):  68-78.  DOI: 10.11686/cyxb20140408

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Two winter wheat cultivars with different drought tolerance were performed to investigate the relationship between the grain filling and the accumulation and remobilization of water soluble carbohydrates (WSC) in flag leaves and different internodes of main stems during the grain filling in the drought stress (DS) and well watered (WW) conditions. Such tested traits as WSC contents,WSC remobilization rates and WSC contribution rates of different organs,grain weight and grain-filling rate were more significantly affected by the water condition,growth stage and/or organ,whereas different tested traits showed significant specificity in response to above-mentioned factors. The variation trend in WSC contents of different organs was of a rise first and then fall during the grain filling. The maximum WSC content of drought-tolerant cultivar Longjian 19 occurred on 18 DAA (days after anthesis) under both the DS and the WW,while did on 12 DAA in water-sensitive cultivar Q9086 in the DS. The DS might substantially increase WSC accumulation in different organs and improve WSC contribution rates to grain weight by remobilizing WSC built up in different organs during the pre-anthesis. The profit was more conducted in peduncle and penultimate internodes of Longjian 19. In this case,WSC contents,in turn,were up to 196.83 and 242.35 mg/g DW,WSC remobilization rates reached to 66.15% and 63.21%,and WSC contribution rates were up to a maximum of 12.48% and 8.67%,respectively. Although the DS shortened the course of grain filling,Longjian 19 still performed higher grain-filling rate and greater grain weight of main spikes. Positive correlations were found not only between WSC contents of different organs and grain-filling rates of main spikes,but also between WSC remobilization rates and its contribution rates. Furthermore,these correlations were significantly higher under the DS than the WW condition. It indicated that drought stress could enhance the accumulation and remobilization of WSC of different organs in wheat,and more buildup of WSC in peduncle and penultimate internodes might play an important role in compensating grain filling under the DS.

Analysis of variation in physio-biochemical characteristics and cold resistance in winter rapeseed F₂ populations

KONG De-jing,WANG Yue,SUN Wan-cang,ZENG Xiu-cun,FANG Yan,LU Mei-hong,YANG Ning-ning

2014, 23(4):  79-86.  DOI: 10.11686/cyxb20140409

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Overwintering rates,seedling habits,SOD activity,and five other physio-biochemical indicators in 103 F₂ populations of a winter rapeseed (Brassica rapa) cross between Longyou 7 and Longyou 9 were studied using variance analysis,correlation analysis,cluster analysis and path analysis. The frequency of all indicators (except SOD) activity in the F₂ populations was approximately normally distributed but with a slight skew. A tremendous transgressive segregation for all indicators was observed in the populations. At a cluster distance of 3.58,F₂ populations were divided into eight groups,with great genetic differences. Correlation analysis showed that all indicators had significant differences in overwintering rates. The path coefficient and correlation coefficient between all indicators and overwintering rate were consistent,but the explanation of their relationships were better explained by the path coefficient. Through path analysis,the relative importance in descending order of B. rapa winter survival rate was: Seedling habits,SOD activity,MDA content,free proline content,POD activity,CAT activity,and soluble protein content. Seedling habits directly impacted winter survival rates,and the influence reached 79.8%,but CAT activity was mainly through indirect effects and the indirect affect rate was 68.7%,with the rest of the indexes co-acting through both direct and indirect effects. These results provide useful information for quantitative trait loci (QTL) mapping.

Study on the flowering dynamic,pollen viability and stigma receptivity of Kochia prostrate

GUO Hong-chao,YAN Cheng,WEI Yan

2014, 23(4):  87-93.  DOI: 10.11686/cyxb20140410

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Kochia prostrata is subshrub of Chenopodiaceae and fine pasture inhabiting arid zone. Flowering phenology,flowering dynamic,pollen viability and stigma receptivity of K. prostrata were studied. For spicate inflorescence of K. prostrata middle flowers bloomed first,then lower flowers,the upper flowers bloomed at last. For a poly-capitulum,central florets bloomed earlier than bilateral ones. The flowering course of single flower of this species can be divided into female subage and male subage. The female subage can lasted 10 to 12 days and the male subage was 1 day. This species produces two types stigmas and anthers in colour (red and yellow).There are four combination types of stigma and anther in the K. prostrata population. The pollen viability of K. prostrata was highest at initial stage (>80%),higher on the 4 to 8 hours after flowering,and then reduced evidently. The pollen viability of yellow-anthers are longer than the red-stigmas. The change tendency of receptivity of the two colour stigmas is similar. The stigma receptivity appeared on the first day of stigma showing from tepals,and then enhanced with the growth of stigma. The stigma receptivity were highest on the 8 to 12 days after flowering. The period of stigma receptivity was about 12 days,account for 92.3% of single flower blooming. The pollen-ovule ratio (P/O) of K. prostrata was 61900-64200. Based on Cruden’s criterion,the breeding system would be outcross. Floral dynamics,pollen viability and stigma receptivity have significant value to understanding the evolution of breeding system and the ecological adaptive mechanism.

A study on fermentation quality of Italian ryegrass and soybean straw mixed silage

YAN Yan-hong,LI Jun-lin,GUO Xu-sheng,YU Zhu,ZHANG Xin-quan,SUN Juan-juan,LUO Yan

2014, 23(4):  94-99.  DOI: 10.11686/cyxb20140411

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The mixed fermentation quality of Italian ryegrass (Lolium multiflorum) and soybean (Glycine max) straw was studied through the following proportions of 10∶0 (Control),9∶1 (S₁),8∶2 (S₂),7∶3 (S₃) and 6∶4 (S₄). The silos for each mixture were opened on 42 d after ensiling and the fermentation quality was measured. The results showed that the dry matter content was increased significantly,but the NH₃-N to total nitrogen (TN) ratio and the content of volatile fatty acids were significantly decreased by adding soybean straw. The butyric acid content and NH₃-N to TN ratio were decreased markedly in the treatment of S₂ and S₃. The V-Scores were higher as compared with the control,S₂ and S₃ treatment indicated good fermentation quality. It was suggested that the 7∶3 mixed proportions of Italian ryegrass and soybean straw was best for improving fermentation quality and maximum using soybean straw.

Effect of adding an inoculant and molasses on fermentation quality of mixed silage of hull-lessbarley straw and perennial ryegrass in Tibet

ZHAO Qing-jie,YUAN Xian-jun,GUO Gang,WEN Ai-you,BA Sang,WANG Qi,SHEN Zhen-xi,YU Cheng-qun,SHAO Tao

2014, 23(4):  100-106.  DOI: 10.11686/cyxb20140412

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To evaluate the effect of adding an inoculant (LAB) or/and molasses (M) on the fermentation quality of mixed silage of hull-lessbarley straw and perennial ryegrass during ensiling,an experiment was designed with the following treatments: control,LAB,molasses and LAB+molasses. Six silos per treatment were opened 7,24 and 45 days after ensiling and the fermentation quality was measured. Adding LAB accelerated the onset of lactic acid fermentation; however,there were increases in butyric acid and ammonia/total N during the latter stage of ensiling due to the lack of fermentable substrate. The addition of molasses supplied the fermentative substrates,which improved the fermentation quality and significantly (P<0.05) increased the lactic acid content,significantly (P<0.05) reduced pH and decreased propionic and butyric acid contents. Combination addition of LAB and molasses significantly improved the fermentation quality of mixed silage compared with LAB addition alone,but there were no significant differences in fermentation quality between silages treated by M alone and by M plus LAB. It is concluded that the lack of fermentation substrate is the major limiting factor for mixed silage of hull-lessbarley straw and perennial ryegrass.

Analysis of characteristics of a hexaploid somatic mutant of hybrid Pennisetum

ZHONG Xiao-xian,LIU Zhi-wei,LIU Wei-guo,CUI Li-li,WU Juan-zi,ZHANG Jian-li

2014, 23(4):  107-113.  DOI: 10.11686/cyxb20140413

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The characteristics of hexaploid somatic mutant CHP2009-14 which was regenerated from embryonic callus treated by colchicine,CHP2009-14 and a triploid hybrid of Tift23A and Pennisetum purpureum cv. Sumu No.2 (CK) were studied. Specific characteristics analysed were morphological traits,plant nutrition value,leaf stomatal characteristics,and ploidy identification by flow cytometry. Compared to those of the CK after 92 days growth in saline soil,the leaf color of CHP2009-14 was dark green,the chlorophyll content increased 10.51% (P<0.05),there were many more hairs in the leaves and sheaths; the plant height was reduced 26.34% (P<0.01); the leaf length decreased by 20.06% (P<0.01) and the leaf thickness increased by 16.41% (P<0.01).The stem/leaf ratio was reduced 43.61% (P<0.01) and number of tillers increased by 44.62% (P<0.01). The leaf width was not significantly different. Digestibility in vitro,crude protein,ash and acid detergent fiber were significantly increased by 6.94% (P<0.05),62.34% (P<0.01),17.35% (P<0.01) and 10.24% (P<0.01),respectively. Neutral detergent fiber decreased by 3.35% and acid detergent fiber increased by 0.50% (P>0.05). Fresh grass yield increased by 0.87% (P>0.05) and dry matter yield decreased by 3.27%(P>0.05). Compared to those of the CK,the stomatal density of CHP2009-14 in the upper and lower epidermis was lower by 65.20% (P<0.01) and 35.71% (P<0.01),the stomatal length and width increased by 47.71% (P<0.01) and 30.53% (P<0.01),51.54% (P<0.01) and 34.17% (P<0.01),respectively,and the stomatal area was 2.07 and 1.54 times that of the CK. Flow cytometry analysis showed that the nuclear DNA contents of CHP2009-14 was twice that of the CK.

Effects of paclobutrazol on the photosynthetic characteristics and ultrastructure of Dahlia pinnata leaves

FENG Li-juan,YUAN Zhao-he,YIN Yan-lei,ZHAO Xue-qing

2014, 23(4):  114-121.  DOI: 10.11686/cyxb20140414

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To study the effects of paclobutrazol on growth,development,photosynthetic characteristics and chloroplast ultrastructure in Dahlia pinnata,the cultivar ‘Longshangxiongying’ was treated with different concentrations of paclobutrazol and water was used as the control. Plant height was dwarfed,internodes were shortened,flower diameter increased and ornamental values enhanced under different paclobutrazol treatments. Chlorophyll contents and net photosynthetic rate initially increased but then decreased and were highest at the 24^th day. Variation trends of transpiration rate,stomatal conductance and intercellular CO₂ concentration differed with increasing treatment time. The photosynthetic capacity reduction was due to both stomatal factors and non-stomatal factors. At concentrations of 75 mg/L and less,the chloroplast and mitochondrion structure were completed,the grana and grana lamella arranged appropriately,and the numbers of grana and grana lamella were higher than in the control,while the photosynthetic capacities were stronger. In the 100 and 125 mg/L treatments,chloroplast and mitochondrial structures were damaged and plasmolysis occurred. The growth of grana and grana lamella was incomplete. These factors seriously influenced photosynthesis. The effect of 75 mg/L paclobutrazol treatment was the best. In this treatment,chlorophyll contents of D. pinnata leaves were the highest,photosynthesis capacity was the strongest and the ornamental value of the D. pinnata were the highest.

Cloning and expression analysis of two WRKY transcription factors from the rare recretohalophyte Reaumuria trigyna

WANG Jia,ZHENG Lin-lin,GU Tian-pei,WANG Xue-feng,WANG Ying-chun

2014, 23(4):  122-129.  DOI: 10.11686/cyxb20140415

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Reaumuria trigyna is an endangered small shrub thriving in vast arid areas of Inner Mongolia. This species has developed a distinct morphology and physiology to adapt to the semi-desert environment. The WRKY gene family are plant-specific transcription factors which play important roles in the regulation of plant development,metabolism,and diverse biotic and abiotic stresses. Based on R. trigyna transcriptome data,two cDNA fragments (annotated as WRKY transcription factors) which were significantly upregulated after salt treatment were selected. Using rapid amplification of cDNA ends (RACE),these two WRKY transcription factors were cloned from R. trigyna. Blasted in the NCBI database,the homology to Arabidopsis AtWRKY33 were 79% and 87%,so they were named RtWRKY33-1 and RtWRKY33-2 (GenBank accession number KF421158 and KF421159),respectively. The full-length of the RtWRKY33-1 was 2163 bp and included a 1681 bp open reading frame (ORF) which encoded 573 amino acids. The full-length of RtWRKY33-2 was 2155 bp and included a 1776 bp ORF encoding 591 amino acids. Amino acid sequence analysis indicated that they were typical of class I WRKY transcription factors. Protein structure prediction analysis found that the primary structure and secondary structure in the WRKY domain of the amino acid sequence had structures characteristic of high similarity. However,in the non-conserved domains,especially the N-terminus (1 to 80 aa range),before the first WRKY domain (190 to 240 aa range) and between two WRKY domains (430 to 450 aa range),there were significant differences that may influence the function of these two genes. Semi-quantitative RT-PCR analysis showed that four abiotic stresses can induce the expression of these two genes. However,RtWRKY33-2 was mainly inducted by salt,cold and ABA,while RtWRKY33-2 responded faster to drought stress. These two genes in R. trigyna may play a different rolein abiotic stress responses. This research is a basis for study on the regulation mechanism of WRKY33 transcription factors in R. trigyna.

Cloning and tissue-specific expression analysis of phenylalanine ammonia-lyase gene fragment in Angelica sinensis

LUO Jun,WANG Yin-quan,WEN Sui-chao,LI Jing,ZHANG Jin-lin,XIA Qi

2014, 23(4):  130-137.  DOI: 10.11686/cyxb20140416

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Phenylalanine ammonia-lyase (PAL) plays an important role in the phenylpropanoid metabolic pathway in higher plants and is closely related to the synthesis of major secondary metabolites. Ferulic acid,a major active ingredient in Angelica sinensis,is one of the intermediate products in phenylpropanoid pathway. In this paper,the cDNA fragment of phenylalanine ammonia-lyase gene (PAL) was cloned and its tissue-specific expression by fluorescence quantitative PCR was analyzed for exploring the mechanism of biosynthesis and accumulation of ferulic acid in Angelica sinensis. A pair of amplification primers was designed according to the conservative sequences of the cloned PAL. Extracting the total RNA from the leaf tissue of A. sinensis as a template,PAL fragments were obtained by reverse transcription polymerase chain reaction (RT-PCR) and connected to pGEM-T Easy vector then transformed into Escherichia coli DH5α. The positive clone identified by PCR was sequenced and 706 bp sequence (accession number: KJ000258) including termination codon TAA was obtained,which encoding 232 amino acids. The sequence identity analysis suggested that both the nucleotide sequence and its corresponding amino acid sequence shared over 80% of homology with GenBank PALs from Glehnia littoralis and five other higher plant species. Taking actin of A. sinensis as a reference gene,SYBR green fluorescence quantitative RT-PCR was used to detect the relative expression levels of PAL in leaf,stem and root of A. sinensis. The findings were PAL expressed at the highest level in leaf,followed by stem and root,and the relative expression levels in leaf and stem was 7.5 and 2.7 times relative to root,respectively.

Vector construction and over-expression of an avian influenza virus hemagglutinin (HA) in transgenic Lotus corniculatus

ZHANG Wei-wei,YUAN Bei,ZHANG Zhan-lu,ZHAO Yang-min,XU Bing-liang,WU Yan-min

2014, 23(4):  138-145.  DOI: 10.11686/cyxb20140417

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A safe and efficient plant expression vector,HA-LTB,which added double 35S promoter,Ω enhancer,endoplasmic reticulum retention signal KDEL sequence and extended poly (A) sequence was constructed. Twenty one transgenic Lotus corniculatus plants were obtained by the Agrobacterium-mediated method and the results of PCR and RT-PCR showed that the HA-LTB gene had been obtained from the plant genome. ELISA results of the B subunit of Escherichia coli heat-labile enterotoxin (LTB) showed that LTB could be expressed in transgenic L. corniculatus and had immunogenicity. It was concluded that hemagglutinin (HA) which was fused with LTB had immune activity. The highest expressions of LTB and HA were 0.086 μg/mg (crude protein extracts) and 0.25 μg/mg (crude protein extracts) respectively which has approached advanced international standards. A high level exogenous antigen protein expression platform which was a basis for research on the H5N1 avian influenza vaccine was established by optimizing the expression vector.

Organic acid composition analysis of root exudation of Chinese milk vetch genotypes

LIN Xin-jian,LAN Zhong-ming,ZHANG Hui,WANG Fei,HE Chun-mei

2014, 23(4):  146-152.  DOI: 10.11686/cyxb20140418

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A low soil phosphorus content is one of the most important limiting factors affecting crop growth. Root exudations of organic acids which can activate insoluble phosphate have an important effect on enhancing crop P nutrition. Nine Chinese milk vetch (Astragalus sinicus) species were selected as research objects using soil culture in-situ methods to collect root exudates (organic acids) and high performance liquid chromatography (HPLC) was used to measure organic acid compositions and contents. Chinese milk vetch root exudates contain oxalic acid,malic acid,lactic acid,acetic acid,and succinic acid. There were significant differences between species,but the coefficient of individual species had large variations. There were significant positive correlations between malic acid and biomass,and between succinic acid and biomass. Thus,to some extent,the amount of malic and succinic acid secretion could represent the level of Chinese milk vetch biomass. In addition,the correlation between the total amount of organic acids and biomass was significantly (P<0.05) positive. Therefore,the level of exudation of organic acids,malic and succinic acids in particular,has a significant impact on Chinese milk vetch plant growth and biomass.

Changes of the content and biomass of cell wall components and calculated ethanol yields in Pennisetum purpureum and hybrid Pennisetum during the growing period

WU Juan-zi,ZHANG Jian-li,PAN Yu-mei,LIU Zhi-wei,ZHONG Xiao-xian

2014, 23(4):  153-161.  DOI: 10.11686/cyxb20140419

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Changes in the cell wall components,biomass and calculated ethanol yields (CEY) from cellulose and hemicelluloses of Pennisetum purpureum cv. Sumu No.2 (PP) and hybrid Pennisetum (HP) during 83-173 days after transplanting seedlings (DATS) in Nanjing were studied. With an extension of the growing period,the cellulose (CEL) contents of stems and leaves gradually decreased,but the hemicelluloses (HMC) and the acid detergent lignin (ADL) contents of stems gradually increased in these two species. During the observed growing period,the CEL content of leaves was significantly (P<0.01) higher,while the HMC leaf contents were lower (P<0.01) than those of stems,and the HMC of leaves in PP was higher (P<0.01) than that in HP. During 114-173 days,the CEL content of stems was lower (P<0.05),while the HMC (P<0.01) and ADL (P<0.05) were higher in PP than those in HP. During 83-114 days,the biomass of all cell wall components and the total CEY steadily increased in PP and in HP. There was no significant difference between the two species in CEL and ADL biomass,however,the HMC of stems was much higher than that in leaves (P<0.01). The total CEY and CEY of leaves between the two species were not significantly different,but the CEY of stems was much higher than that of leaves (P<0.01). During 114-173 days,the biomass of all cell wall components and total CEY had been increasing dramatically,and the majority of the increased yields came from the stems. The HMC,ADL and the CEY of leaves had no obvious difference between the two species,but the biomass of CEL and the total CEY in HP was significantly (P<0.01) higher than those in PP.

Effects of light intensity on biological characteristics, physiological indexes and flavone content of Kalimeris indica

LI Zhong-lin,GUO Kai-xiu,ZHOU Shou-biao,ZHENG He-quan,LIU Kun

2014, 23(4):  162-170.  DOI: 10.11686/cyxb20140420

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The effects of light intensity (100%,62.29%,35.17% of full light radiation) and different exposure times on biological characteristics,physiological indexes and flavone content of Kalimeris indica were studied.1) With increased treatment time,the internode-length of all treatment types showed an increasing trend,but shading inhibited K. indica’s internode-length elongation,especially at 62.29% of full light radiation. Shading stimulated K. indica’s branching ability at 35.17% of full light radiation,but this was not significant at 62.29% of full light radiation. Shading,especially light shading,inhibited erect growth of K. indica. Deeper shading (35.17% of full light radiation) was conducive to increased leaf length,width and sawtooth,but was not significant at 62.29% of full light radiation.2) Chlorophyll a,b and total chlorophyll content decreased at 35.17% of full light radiation. The content of O2-· increased after an initial decrease and then decreased again with an increase of exposure time to light radiation. The activity of SOD and the MDA content increased after an initial decrease with time while the activity of POD showed the opposite trend. With a reduction of light intensity,the activity of POD and MDA content increased and the activity of SOD also increased after an initial decrease. At 35.17% of full light radiation,K. indica’s CAT activity was significantly lower than that of the control. 3)With a decline of light intensity,the flavonoids content decreased in the leaves,increased in the roots and was highest in the stems at 62.29% of full light radiation.

Growth and physiological responses of three warm-season turfgrasses to lead stress

LI Xi,WU Ya-jiao,SUN Ling-xia

2014, 23(4):  171-180.  DOI: 10.11686/cyxb20140421

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In order to explore the mechanism of Pb accumulation and transportation in plant tissue,the growth and physiological responses of turfgrass under soil Pb stress were evaluated in a pot experiment with three warm-season turfgrass species: Eremochloa ophiuroides (centipedegrass),Cynodon dactylon (bermudagrass),and Zoysia japonica (zoysiagrass). By applying Pb of different concentrations to the soil,CK(0 mg/kg)and five Pb treatments as the following 250,500,1000,2000,4000 mg/kg were set in this experiment. Our results showed that there is a significant decrease of the visual quality and leaf relative water content under 4000 mg/kg treatment comparing with control. Leaf chlorophyll a and b content significantly reduced under 4000 mg/kg treatment comparing with control among all three turfgrasses. The electrolyte leakage in leave gradually rises with the increase of Pb level among all three turfgrasses. These results suggested that cell membrane of leave is damaged by application of Pb. The antioxidant defense system (superoxide dismutase/SOD,catalase/CAT,peroxidase/POD) was greatly activated under the various Pb stress among three turfgrasses species. Under all four Pb treatments in centipedgrass,the activity of SOD gradually rises and reaches a maximum at 20 day after Pb application,and the activity of CAT at day 5 after Pb treatment is greatly higher than that in control. While the activity of POD increases significantly only under 2000 and 4000 mg/kg Pb treatments and reaches the maximum at day 15 after Pb application in centipedigrass. Under all four Pb treatments in bermudagrass,the activity of SOD rises at day 5 after Pb treatment and boosts a maximum at day 25,and the activity of CAT reaches a maximum at 15 day after treatment. While the activity of POD in Pb treatments rises gradually with the accumulation of Pb in soil and reaches a maximum at day 30 in all Pb treatments. The activity of SOD is significantly higher under 4000 mg/kg treatment than that in control and reaches a maximum at 15 day after treatment in zoysiagrass. While the activity of POD reaches a maximum at day 25 after treatment and then drops at day 30,activity of CAT shows a similar trend as that of POD and reaches a maximum at day 15 after treatment. These data implied that the protection capacity of three enzymes varied among three grass species under lead stress. Combing with the growth effect,we concluded that Pb resistance from high to low among three turfgrass species is in the following order: bermudagrass>zoysiagrass>centipedegrass.

Physiological and ecophysiological responses of Humulus scandens seedlings to chromium stress

WANG Bi-xia,XU Xiao,LI Xiao-feng

2014, 23(4):  181-188.  DOI: 10.11686/cyxb20140422

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The ecophysiological characteristics and photosynthesis of Humulus scandens seedlings under chromium stress (0,50,200,300,and 500 mmol/L Cr³⁺) were studied. Under 50 mmol/L stress,the net photosynthetic rate (Pn) and instant water use efficiency (WUE) increased significantly compared with the CK butstomatal conductance (G_s),transpiration rate (T_r),stomatal limitation (L_s),intercellular CO₂ concentration (C_i) and chlorophyll contents were not significantly different. Under 200-300 mmol/L stress,actual maximal fluorescence (F_m'),actual minimum fluorescence (F_o'),dark fluorescence yield (F_o),maximal fluorescence yield (F_m),variable fluorescence (F_v),potential activity of PSⅡ(F_v/F_o),maximum quantum yield of PSⅡ(F_v/F_m) and proportion yield of PSⅡ(qP) gradually decreased with an increase of Cr³⁺ stress,while L_s and WUE_i initially increased but then decreased,whereas C_i initially decreased but then increased. The opposite side of electron transport rate (E_TR) and malonaldehyde (MDA) showed a tendency to increase,while the coefficient of non-photochemical quenching (qN) showed irregular changes. In particular,the P_n,T_r,L_s,WUE_i,content of MDA and qN declined significantly in 500 mmol/L Cr³⁺ stress,but the C_i and other chlorophyll fluorescence parameters suddenly increased. In summer,there was a clear difference of gas change,content of MDA and chlorophyll and chlorophyll fluorescence parameters. Although some physiological indexes declined in the H. scandens seedlings with increasing Cr³⁺ stress,but showed a positive response,keep certain photosynthesis under high Cr³⁺ stress,and its tolerance to Cr³⁺ stress was the strongest.

Effects of a microorganism on grass seedling physiological and biochemical characteristics when grown in Cr(Ⅵ) polluted soil

GAO Hai-ning,MA Guo-tai,LI Cai-xia,CHEN Yong,SONG Tao,ZHANG Yong,JIAO Yang

2014, 23(4):  189-194.  DOI: 10.11686/cyxb20140423

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Cr (Ⅵ) polluted soil treated with a particular species of microorganism during the growing period was used in pot cultures of seedlings of Festuca arundinacea and Lolium perenne to investigate the effects on physiological and biochemical characteristics of the seedlings in Cr (Ⅵ) polluted soil. Treatment with the microbe during the grass seedling growing period significantly reduced Cr accumulation in the root,but increased it in the leaves. At the same time,the damage to cell membrane permeability and the malondialdehyde (MDA) content as well as the enzyme activities of POD,SOD and CAT were improved. In addition,the microorganism agent reduced Cr (Ⅵ) content in Cr (Ⅵ) polluted soil.Addition of the agent to Cr (Ⅵ) contaminated soil had an improvement effect on the soil.

Effects of arbuscular mycorrhizal fungus Glomus mosseae on the growth characteristics of Festuca arundinacea under salt stress conditions

YANG Hai-xia,LIU Run-jin,GUO Shao-xia

2014, 23(4):  195-203.  DOI: 10.11686/cyxb20140424

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As the global changes,the soil salinization becomes more and more serious and directly impacts plant growth. Festuca arundinacea is one of important lawn plants influenced with arbuscular mycorrhizal (AM) fungi and soil salinization. So how to improve the salt tolerance of F. arundinacea,is one of the urgent problems to be solved. The purpose of the present research was to evaluate the effects of AM fungi on improving salt tolerance of F. arundinacea,and to explore the mechanism of increasing salt tolerance of F. arundinacea by AM fungi. F. arundinacea seeds were inoculated with AM fungus Glomus mosseae and treated with different NaCl concentration (0%,0.8%,1.2% and 1.6%) under pot conditions in a greenhouse. The activity of antioxidant enzymes (SOD,POD and CAT),contents of antioxidant (AsA),soluble sugar,proline,nutrient elements (N,P,S,Zn,K,Ca and Mg),ABA (abscisic),IPA (isopentenyl adenosine),IAA (indole-3-acetic acid),GA (gibberellin) and K/Na,Mg/Na,Ca/Na increased,in leaves of F. arundinacea plants colonized with G. mosseae,while the content of methane dicarboxylic aldehyde (MDA),Na⁺ and Cl^- decreased,as well as membrane permeability,compared to the noninoculation control. It was concluded that AM fungi could improve plant salt tolerance through improving nutrient absorption,osmotic regulation and the reaction of antioxidant system of plants,maintaining hormonal balance,reducing toxicity of Na⁺ and Cl^- and damage caused by oxidative stress.

Effect of low nitrogen stress on different low nitrogen tolerance maize cultivars seedling stage growth and physiological characteristics

LI Qiang,LUO Yan-hong,LONG Wen-jing,KONG Fan-lei,YANG Shi-min,YUAN Ji-chao

2014, 23(4):  204-212.  DOI: 10.11686/cyxb20140425

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The response of maize seedling stage growth and physiological characteristics were studied in 4 different low nitrogen tolerance maize cultivars in a two years pot experiment. The results showed that the plant height,leaf area,dry weight of shoot,dry weight of plant,nitrogen accumulation,shoot nitrogen distribution,chlorophyll content and soluble protein content of the 4 maize hybrids declined sharply under the low nitrogen stress conditions. However,root-shoot ratio,root nitrogen distribution,nitrogen physiological efficiency,the content of soluble sugar,proline,MDA (malondialdehyde) and POD (peroxidase) activity were significantly increased; and there was insignificant difference in dry weight of root under the different nitrogen levels. Compared with low nitrogen sensitive maize cultivars,the variation of plant height,leaf area,dry weight of shoot,dry weight of plant,root-shoot ratio,nitrogen accumulation,shoot nitrogen distribution,root nitrogen distribution,the content of chlorophyll,soluble protein and MDA are lower,while the variation of nitrogen physiological efficiency,the content of soluble sugar and proline,and the activity of POD are higher in low nitrogen tolerant maize cultivars under the low nitrogen stress. The results showed that compared with low nitrogen sensitive cultivars,the low nitrogen tolerant cultivars kept stronger photosynthetic capacity by higher shoot nitrogen distribution,higher chlorophyll content and bigger leaf area,reduced the damage of membrane lipid peroxidation and delayed the leaf senescence by higher content of organic osmotic,such as soluble protein,soluble sugar and proline,and POD activity,meanwhile the low nitrogen environment adaptability of low nitrogen tolerant maize cultivars was improved.

The effect of water stress on growth and biomass of Medicago sativa cv. Xinjiangdaye

LUO Yong-zhong,LI Guang

2014, 23(4):  213-219.  DOI: 10.11686/cyxb20140426

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The effects of growth and biomass accumulation under different soil water stress (90% of field capacity,70%,40%,20%) on Medicago sativa cv. Xinjiangdaye were studied in the pot method. The results showed that height,diameter,number of branches and lateral roots were higher than other treatments,fresh biomass and dry biomass of leaves,stems,root were the largest. When soil moisture content was 70% of field capacity and it was the most fitted for the growth of M. sativa cv. Xinjiangdaye. It was not conductive to the formation of M. sativa cv. Xinjiangdaye biomass when the soil moisture content is too high (90% of field capacity) or too low (20%,40% of field capacity). Soil moisture stress inhibited growth of M. sativa cv. Xinjiangdaye. Height and diameter growth rates were slowed with water stress intensification. The results helped to understand the response of M. sativa cv. Xinjiangdaye to water stress and provided a theoretical basis for the spreading and cultivation of M. sativa cv. Xinjiangdaye under water-saving irrigation in the arid zone agriculture as well as establishing lasting,stable and high-yielding grassland production system.

Physiological response to drought stresses and drought resistances evaluation of different Kentucky bluegrass varieties

GUO Yu-pin,MI Fu-gui,YAN Li-jun,REN Yong-xia,LV Shi-jie,FU Bing-zhe

2014, 23(4):  220-228.  DOI: 10.11686/cyxb20140427

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To compare the drought resistance of bluegrass seedlings,the 14 varieties of Kentucky bluegrass seed were sowing after disinfection in the plastic pots,then thinned after emergence and fixed strains at 2 to 3 true leaf,left 15 uniform growth and distribution plants in every pot and regularly watering to ensure the normal growth of the seedlings. Drought stress trails were identified at 2 to 3 true leaf period by adding the PEG-6000 according to the Michel formula which are: 0 MPa (control),-0.3,-0.6,-0.9,-1.2 MPa in the study. Then supplement water every two days to maintain the concentration. Two groups of drought treatment and control (normal watering) were set to simulate drought stress of 14 bluegrass cultivars and four replications were set by treatment. The physiological and biochemical index,such as chlorophyll (CHL),malondialdehyde (MDA) content,proline (Pro) content,peroxidase (POD) and superoxide dismutase (SOD) activity were measured and analyzed. The content of CHL was decreased; and the content of the Pro,MDA and SOD showed upward trend; the POD activity increased at first and then decreased and finally increase again in the bluegrass seedlings; Drought resistance of 14 bluegrass varieties were obtained by subordinate function the order is: The No.3 Storpy>No.10 Narrow leaf bluegrass>No.1 Meri>No.2 Geronimoi=No.9 Blue apphire>No.7 Kentucky bluegrass>No.11 Kentucky bluegrass>No.4 Kentucky bluegrass>No.5 Wabash>No.8 Bluegrass=No.13 Kentucky>No.14 Kentucky bluegrass>No.6 Monopoly=No.12 Fylking.

Effects of exogenous betaine on the secondary metabolites of Pinellia ternata under drought stress

ZHANG Hong-min,LI Jiao-jiao,HEI Gang-gang,CAO Rui-xia,ZHOU Xin-yu,LI Lin-lin,YANG Wei-xing,WU Neng-biao

2014, 23(4):  229-236.  DOI: 10.11686/cyxb20140428

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To explore the effects of exogenous betaine solution on secondary metabolites and nitrogen metabolism enzyme activities of Pinellia ternata in a drought environment,a water pot control experiment was used. The treatments were D (drought treatment,35%±2% moisture content),D₂₀ (drought treatment with spray of 20 mmol/L betaine),and D₄₀ (drought treatment with spray of 40 mmol/L betaine). Glutamate synthase (GOGAT),glutamine synthetase (GS),glutamic dehydrogenation enzyme (GDH),nitrate,soluble protein,alkaloids,guanosine and adenosine contents of P. ternata were measured in each treatment group. As drought time increased,the GOGAT and GS activities of D₄₀ decreased slower than those of D,and D₂₀,while GDH activity initially increased but then decreased. However,the CK (control group,75%±2% moisture content) group did not change significantly. The alkaloids in the D₄₀ group improved 6.3% (9 days),10.3% (18 days) and 12.3% (27 days),which was higher than those in the D₂₀. The nitrate,alkaloids and guanosine contents increased with time were higher in the D₄₀ group than in the D₂₀ group,although the CK group was the highest. The adenosine content tended to decrease when the drought stress time reached 27 d. At 27 d,the content of soluble protein in the D₄₀ group was 7.3% higher than in the D,as well as 3.1% higher than in the D₂₀.The 40 mmol/L exogenous betaine solution concentrations increased nitrogen metabolism enzyme activities in P. ternata under drought conditions. This may accelerate the inorganic nitrogen assimilation,which is conducive to the accumulation of secondary metabolites and enhances the ability of P. ternata to resist drought stress.

Physiological responses of four cold-season turfgrasses to oxidative stress of SO₂

SUN Ling-xia,SUN Ping,CAI Shi-zhen,LI Xi

2014, 23(4):  237-244.  DOI: 10.11686/cyxb20140429

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The chlorophyll content,membrane lipid peroxidation,osmoregulation substances,and protective enzyme activity of four cold-season turfgrass species (Fescue arundinacea,Lolium perenne,Poa pratensis; Agrostis stolonifera) treated with SO₂ (1.45,2.15,3.56,or 5.01 mg/m³) were measured using artificial simulation,and the resistance to sulfur was evaluated. The MDA content increased to different extents in these four turfgrass species which indicated that the membrane systems were injured under the SO₂ stress. F. arundinacea and L. perenne had increased antioxidant enzyme activities (SOD,POD and CAT) and accumulated compatible solutes content (soluble sugar and proline) against low level SO₂ stress but high concentrations of SO₂ had a significant effect on them. Additionally,A. stolonifera and P. pratensis had a poor resistance to SO₂ toxicity that was directly reflected in the observed appearance,especially for P. pratensis. The damage increased with SO₂ concentration. The results of a comprehensive evaluation showed that the SO₂ resistance of the four species decreased in the order F. arundinacea,L. perenne,A. stolonifera,and P. pratensis. The turfgrass species F. arundinacea and L. perenne would be suitable for urban landscaping in SO₂ polluted areas.

Characteristics of vegetation and soil inorganic nitrogen concentrations under different disturbed habitats in a weak alpine ecosystem

ZHANG Yu-xia,YAO Tuo,WANG Guo-ji,MA Wen-wen,MA Wen-bin

2014, 23(4):  245-252.  DOI: 10.11686/cyxb20140430

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Characteristics of vegetation and soil inorganic nitrogen concentrations under different disturbed habitats (fenced natural grassland, unfenced natural grassland and driveways) were determined and analyzed in a weak alpine grassland ecosystem of Tianzhu. Characteristics were based on field survey for vegetation and the indophenol blue colorimetric method and dual wavelength spectrophotometry for NH4+N and NO3-N concentrations respectively. There was an obvious change between the different degrees of grassland degradation in ground plant species, coverage, height, biomass, and NO3N and NH4+N concentrations which showed a decreasing tendency in the sequence fenced natural grassland＞unfenced natural grassland＞driveway at the same soil depth. NO3-N and NH4+N concentrations decreased with soil depth in comparable disturbed habitats. From April to October NO3-N and NH4+N concentrations initially increased but then decreased and had a peak value in August. There was no significant difference in fenced soil NH4+N concentrations between August and October. In October, NO3N concentration increased in unfenced natural grassland. There were positive correlations between aboveground biomass and NH4+N, NO3-N under the three kinds of disturbed habitats.

Natural vegetation restoration and change of soil enzyme activity on secondary grassland of abandoned land area in the downstream of Shiyang River

WANG Li-de,YAO Tuo,HE Fang-lan,HAN Fu-gui,GUO Chun-xiu,WANG Fang-ling,WEI Lin-yuan

2014, 23(4):  253-261.  DOI: 10.11686/cyxb20140431

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Community characteristics and soil catalase,sucrase,urease and phosphatase activity and distribution in the natural recovery process of vegetation on secondary grassland of abandoned land area of different eras (1,2,3,4,5,8,15,24,31 a) in the downstream of Shiyang river were investigated and analyzed by the method use space instead of time. The results indicate that 34 species of plant can be found in the 9 investigation samples during 31 a succession after abandoned. The vegetation communities of annual herbaceous as constructive species and Perennial herbaceous with individual bush plants as associated species gradually succession to single shrub community. Strong continuity and graduality showed in the process of succession. Besides,most of the soil enzyme from different depth (0-10 cm,10-20 cm,20-30 cm,30-40 cm) of abandoned lands of different eras show significant differences (P<0.01) on the activity. The soil enzyme activity decreased with the increase of soil depth,and that of surface occupies a large proportion in the total enzyme activity of the 4 layer. With the time of succession increased,the general trend of soil enzyme activity declined in a fluctuant way same as that of species richness and diversity index. Soil enzyme activity and vegetation restoration is an interactive process with a feedback between them. Furthermore,the change of soil enzyme activity is slow,and has correlation with crops grew the last year.

Effects of fertilization on soil carbon pool management index and enzyme activities in pasture grown soil of the Karst region

DENG Shao-hong,LIN Ming-yue,LI Fu-sheng,SU Yi-rong,LIU Kun-ping

2014, 23(4):  262-268.  DOI: 10.11686/cyxb20140432

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To understand the effect of fertilization on accumulation and balance of soil organic carbon in the Karst region,the effects of different fertilization treatments on the labile organic carbon content,carbon management index and enzyme activities (amylase,invertase and urease) in pasture grown soil were investigated in a field experiment. Fertilization had significant effects on the labile organic carbon and carbon management index,but affected the activities of three enzymes in the soil differently. Compared to no fertilization,soil labile organic carbon and carbon management index were increased under fertilization,and soil labile organic carbon content increased (695.6%) significantly under the N₂PK treatment. Soil amylase activities were increased by 8.65%-13.80% under low N treatment,but not obviously different under high N treatment. They were reduced by 17.94% under the N₂P treatment. Soil invertase activities were decreased by 2.55%-26.97% under fertilization treatments. Soil urease activities were increased by 87.67%-169.03% under N only and N₂P treatments,but decreased under the N₁P treatment. The results provide a theoretical basis for scientific fertilization and the reduction of farmland carbon emission in the Karst region.

Effects of arbuscular mycorrhizal fungi on aggregate stability, GRSP, and carbohydrates of white clover

WU Qiang-sheng,YUAN Fang-ying,FEI Yong-jun,LI Li,HUANG Yong-ming

2014, 23(4):  269-275.  DOI: 10.11686/cyxb20140433

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The effects of two arbuscular mycorrhizal fungi (Glomus versiforme and Paraglomus occultum) on size distribution of soil water-stable aggregate and aggregate stability,glomalin-related soil protein (GRSP),and carbohydrates of white clover (Trifolium repens) were analyzed. Root mycorrhizal infection ranged from 35% to 75% after 85 days of mycorrhizal inoculation. The inoculated treatments significantly increased shoot,root,and total dry biomass and chlorophyll content. White clover was more dependent on P. occultum than on G. mosseae. The treatments inoculated with arbuscular mycorrhizal fungi also notably increased the content of water-stable aggregate in the size ranges 0.25-0.5 mm and 0.5-1 mm but significantly reduced them in the 1-2 mm size range. There was no effect on water-stable aggregate content in the 2-4 mm size and mean weight diameter (an indicator of soil aggregate stability). Inoculated treatments markedly increased rhizospheric soil easily-extractable GRSP,total GRSP,hot-water extractable and hydrolyzed carbohydrate contents. Correlation analysis showed that root mycorrhizal colonization was highly positively correlated with GRSP production,and GRSP had a positive effect on <1 mm size water-stable aggregates. In addition,the contribution of GRSPs to aggregate stability mainly depends on total GRSP but not on easily-extractable GRSP. GRSP fractions had different contributions to soil carbohydrates.

A study on the mode of insecticidal action and the activity of detoxification enzyme in extracts of Xanthium sibiricum against Lipaphis erysimi and Mythimna separata

ZHANG Jun-xia,ZHANG Xin-hu,SHEN Hui-min

2014, 23(4):  276-284.  DOI: 10.11686/cyxb20140434

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The mode of insecticidal action and the activity of detoxification enzymes (AchE,GSTs,MFO) were studied using three different solvent extracts (acetone,ethanol,chloroform) of Xanthium sibiricum against Lipaphis erysimi and Mythimna separate. The chloroform extracts of X. sibiricum mainly expressed a strong repellency action against L. erysimi: the repellent rate was 94.25% at 4 h with a concentration of 0.05 g/mL,while at 48 h,it was 84.53%; For contact toxicity,the highest mortality rate was 67.24%,and the LC₅₀ was 0.7420 g/mL; Systemic action was extremely weak. For M. separate,the mode of insecticidal action was mainly antifeedant and growth inhibition activity,and the antifeeding corrected mortality rate was as high as 98.27%,and the AFC₅₀ was 0.1985 g/mL; At 72 h,the body weight growth rate was -5.85%,which was significantly different from the CK; Stomach and contact toxicity were weak,and the LC₅₀ were 0.8997 and 1.3070 g/mL respectively. The AchE activity of L. erysimi and M. separata was inhibited by the chloroform extract of X. sibiricum,at 24 h (L.erysimi) and 4 h (M. separate),the inhibition rates of the AchE activity were the highest (37.55% and 25.65%); The activities of GSTs and MFO were not significant.

Effects of tannins from grape pomace on digestibility, metabolism and rumen fermentation in Sheep

ZHAO Dong,ZHENG Chen,LI Fa-di,LI Chong,LI Ting-fu

2014, 23(4):  285-292.  DOI: 10.11686/cyxb20140435

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Four sheep (Suffolk♂×small tail Han-yang♀) of average weight 28 kg were fitted with permanent rumen fistula to investigate the effects of tannins from grape pomace on digestion,metabolism and rumen fermentation in sheep in a 4×4 Latin square design experiment. Condensed tannin (CT) contents in treatments 1,2,3 and 4 were 0.00,0.85,1.70 and 2.25 g/kg DM,respectively. Tannins from grape pomace did not significantly impact the apparent digestibility of dry matter,organic matter,neutral detergent fiber,acid detergent fiber,calcium and phosphorus. However,it significantly (P<0.05) improved the apparent digestibility and retention of nitrogen. It also significantly (P<0.05) reduced the concentration of total nitrogen and protein nitrogen and raised the concentration of urea nitrogen in ruminal fluid,but did not significantly influence the concentration of ammonia nitrogen. In addition,it significantly (P<0.05) increased the propionate molar ratio but reduced the butyrate molar ratio and acetate/propionate ratio. It did not significantly affect the pH,the concentration of total volatile fatty acid,acetate and other acids molar ratio in ruminal fluid. It is concluded that 2.25 g/kg DM tannins from grape pomace can improve feed protein utilization.

The effect of glutamine supplementation on the barrier function of ruminal epithelium during high grain diet feeding in dairy goats

LIU Yu-jie,LIU Jun-hua,XU Ting-ting,ZHU Wei-yun,MAO Sheng-yong

2014, 23(4):  293-299.  DOI: 10.11686/cyxb20140436

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The effect of protected glutamine supplementation on the barrier function of ruminal epithelium in dairy goats fed high grain diet was investigated using twelve dairy goats that were randomly allocated to 1 of 2 treatments: high-grain (HG) diet group (n=6) or glutamine (Gln) supplementation group (n=6,50 g/d Gln supplementation). After four weeks feeding,four goats in each group were slaughtered to characterize the changes in ruminal epithelial structure,tight junction (TJ) proteins mRNA expression,and inflammatory cytokines mRNA expression using H-E dyeing,scanning and transmission electron microscopy and real-time PCR. Compared with the control,Gln addition reduced (P<0.05) the concentration of propionate,and showed a trend to reduce the lactic acid concentration as well but it increased the butyrate concentration (P>0.05). Gln supplementation did not significantly influence the concentrations of acetate,isobutyl rate and total short-chain fatty acids. In addition,Gln addition up-regulated the gene expression of occludin mRNA expression (P<0.05) and reduced (P<0.05) the mRNA levels of TNF-α in the ruminal epithelia,and had a role in protecting the rumen epithelium. These results indicate that glutamine has a potential to maintain the rumen epithelial structural integrity and barrier function during high grain feeding.

A study on snow fraction mapping based on hierarchical dynamic endmember spectral mixture analysis (DESMA) over Northern Xinjiang

LIU Yan,YANG Yun,LI Yang

2014, 23(4):  300-310.  DOI: 10.11686/cyxb20140437

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Due to cloudy days often in winter and an influence of topography and vegetation as well as uneven snow cover distribution in the area over northern Xinjiang,it is very hard to achieve a snow fraction mapping product with high accuracy using remote sensing images. In order to make snow fraction mapping more accurate,a snow quantitative inversion method based on hierarchical dynamic endmember spectral mixture analysis (DESMA) technology for snow fraction mapping using MODIS data acquired in the study areas suggested. The details of the proposed method areas follows: Image endmembers libraries and reference endmembers libraries were initially built. Then,multi-level category analysis from a coarse to a fine scale on the entire image of the study area was carried out. Two-endmember or three-endmember models for the whole MODIS data was used to unmix each pixel at each level and all pixels were classified into one of two categories: pixels containing snow endmembers and pixels without snow endmembers. Only those pixels containing snow endmembers were further unmixed using DESMA technology to achieve a more refined classification in a finer layer. Unmixing layer by layer,it produced a classification result for each layer. Finally,a snow fraction mapping product with higher precision was generated by combining classification results from each layer. The experiments showed that the suggestion of unmixing using DESMA technology when a smaller number of endmember models(e.g. two- or three-endmembers),is selected then a snow fraction mapping product with the highest overall classification accuracy of 87% can be achieved. The accuracy of snow fraction mapping will be lower if the number of endmembers used in the unmixing model is larger than three. This suggestion has also been verified by snow-cover and vegetation distribution maps derived from HJ CCD remote sensing data and field data of snow-cover.

A review on grassland carrying capacity (Ⅱ): Parameters and calculation methods

XU Min-yun,GAO Li-jie,LI Yun-qi

2014, 23(4):  311-321.  DOI: 10.11686/cyxb20140438

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The traditional technique for determining grassland carrying capacity (CC) is to calculate the total amount of forage at the end of the growing season,multiply this by a correction factor,and then divide by the average yearly feed requirements of a livestock unit. But there has been no consensus on the correction factors and time span. For convenience of management,ananimal unit (AU) is defined,based on the grazing pressure on grassland or grass consumption of certain specific animals,as the standard so other animals can be converted into animal units by comparing the same items. Currently,the most widely used animal units are animal unit (cow unit) and sheep unit (SU). But the AU is often defined on a live body weight (LBW) basis,which does not distinguish between physiological stages that may affect forage intake. What’s more,some forage species are not preferred by some kinds of livestock,and some ranges are better suited to one kind of livestock than to another; Animal units for different animal species should be adjusted based on the average dietary overlaps of these animal species on a specific type of range for calculating pasture-specific substitution ratios. It is important for pastoralist to be aware of use levels,residual vegetation and other grazing impacts during the period of use as well as utilization at the end of the growing season. Various methods were developed to estimate proper utilization rates,which can fall into two categories:estimation and measurement. The rule-of-thumb takes half-leave,half-use has been a standard in the range management profession for years. But forage output fluctuates considerably between years in response to changing climatic conditions and the concept of utilization rates means how it should be used in pasture management and has led to some confusion because a variety of ways in calculating pasture utilization rates are often not clearly defined. Furthermore,the choice of a proper use value has a profound effect on the estimate of CC. Based on research progress,the concept,measurement method and application dispute of parameters such as grassland output,proper utilization rate,livestock substitute rate et al. for CC calculation are summarized. The calculation method and adjustment factors for CC are also summarized to provide reference for grazing management decisions.

A study on advances in plant photorespiration

GUO Yu-peng

2014, 23(4):  322-329.  DOI: 10.11686/cyxb20140439

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Photorespiration,a tightly correlated process with photosynthesis,is initiated by the oxygenation of ribulose-1,5-bisphosphate (RuBP),a process catalyzed by RuBP carboxylase/oxygenase. In this reaction,2-phosphoglycolate,a compound toxic to photosynthesis is produced and recycled back to phosphoglycerate (3-PGA),a Calvin cycle intermediate. Because of production of CO₂ and NH₃,and the considerable loss of energy,this cycle is considered a wasteful process. However,under high light intensities,photorespiration could also alleviate photo-inhibition and photo-oxydation by adjustment of electron flow and consumption of excess energy. The gene cloning of this process could facilitate studies on physiological functions and increase crop yields by modifying key genes. In this article,the process,physiological functions,gene cloning and regulation of this pathway are summarized.

Research progress on alfalfa bacterial diseases

ZHANG Zhen-fen,NAN Zhi-biao

2014, 23(4):  330-342.  DOI: 10.11686/cyxb20140440

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Research progress on alfalfa bacterial diseases,both in China and overseas,are reviewed. Nine bacterial diseases of alfalfa were recorded in worldwide and they were caused by 8 bacterial pathogens belonging to 6 genera. They were alfalfa bacterial wilt caused by the gram-positive bacterium (Clavibacter michiganensisi subsp. insidiosus),and 8 bacterial diseases of alfalfa caused by gram-negative bacteria:bacterial sprout wilt (Erwinia persicinus),bacterial sprout rot (Erwinia chrysanthemi pv. chrysanthemi),crown gall (Agrobacterium tumefaciens),crown and root rot complex (Pseudomonas viridiflava),bacterial leaf spot and damping off (Xanthomonas campestris pv. alfalfae),bacterial stem blight (Pseudomonas syringae pv. syringae) and dwarf (Xylella fastidiosa). Alfalfa bacterial leaf spot and bacterial stem blight were recorded,and bacterial sprout wilt,a new disease,was first reported in 2012,in China. In this paper,the types of alfalfa bacterial diseases and their characteristics,distribution and host range are summarized and listed. The symptoms distinguishing methods and pathogen phenotypic characteristics of alfalfa bacterial diseases are detailed. The frequently used phenotypic characteristic identification methods for alfalfa bacterial pathogen were used together with 16S rRNA sequence analysis and the Biolog identification system.

Responses of soil microbial functional diversity to nitrogen and water input in Stipa baicalensiss teppe, Inner Mongolia, Northern China

WANG Jie,LI Gang,XIU Wei-ming,ZHAO Jian-ning,WANG Hui,YANG Dian-lin

2014, 23(4):  343-350.  DOI: 10.11686/cyxb20140441

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The effects of nitrogen fertilizer (0,15,30,50,100,150,200,300 kg N/hm²) and water on soil microbial functional diversity in Stipa baicalensis steppe were explored for 2 years by the Biolog method. Compared with non-irrigation,water enhanced soil microbial metabolic activity and the utilization ability of carbon sources. The interaction of irrigation and the N₁₅ level of fertilizer significantly increased the utilization ability of carbon source and functional diversity of soil microorganisms. Higher N fertilizer (N₁₀₀,N₁₅₀,N₂₀₀ and N₃₀₀) significantly reduced the richness and evenness index of microorganisms,but increased the dominance index. Irrigation and N fertilizer led to changes not only of functional diversity,but also of carbon source utilization mode and metabolic function of the microbial communities. Principal component analysis (PCA) showed that there was a very significant difference in the carbon source utilization mode of the microbial communities between the lower fertilizer treatments and higher fertilizer treatments indicating that N fertilizer was the main impact factor. Carbohydrates,amino acids,intermediate metabolites,and secondary metabolites were the main carbon source utilized by the microbial communities. In addition,organic carbon,total N,and available N in soil had a close relationship to microbial functional diversity.

Effect of harvest time and harvest method on seed yield and quality of Brachiaria decumbens ‘basilisk’

ZHANG Mei-yan, XUE Shi-ming, CUI Ling-yan, XU Chi, KUANG Chong-yi, HUANG Mei-fen

2014, 23(4):  351-356.  DOI: 10.11686/cyxb20140442

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The experiments were conducted to study the effect on seed yield, 1000 seeds weight and seed viability of Brachiaria decumbens ‘basilisk’ under different harvest time including the 38 d after the onset of the blooming period and different harvest methods including tying with traditional cutting, tying bag and manual patting harvest methods. The results showed that highest seed yield, 1000 seeds weight and seed viability were obtained with harvesting 38 d after the onset of the blooming period, compared to the other harvest time treatment which including 28, 33, 43 and 48 d treatments. Compared to the traditional cutting method and manual patting methods, the highest seed yield and 1000 seeds weight were obtained with harvesting by tying bag, which was 202.37 kg/hm² and 5.11 g, separately. It was indicated that 38 d after the onset of the blooming period and tying bag was the best harvest time and harvest method of ‘basilisk’ seed production in Yunnan province, respectively.

solation of anaerobic fungi from the rumen and faeces of goat and comparison of fermentation activity between isolates in vitro

MAO Sheng-yong, YAO Wen, CHEN Yong

2014, 23(4):  357-363.  DOI: 10.11686/cyxb20140443

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The anaerobic fungi in rumen fluid and faeces of two local goats in Nanjing area were isolated. The genera Neocallimastix, Piromyces, Orpinomyces and Anaeromyces were isolated from the rumen liquid of goat, and the genera Neocallimastix and Piromyces were isolated from the fresh faeces. The ability to degrade rice straw, wheat straw and cornstalk by these isolates was compared. The degradability of rice straw by all isolates was greater than 30%, while that of corn straw was less than 25%. When compared with the isolates from rumen liquid, the degradation by species isolated from faeces had a lower total gas production and degradability of dry matter when the three forages were used as substrates. There were some differences in degradability of forage by these organisms which could be explained by the differences in composition of the three substrates and by the characteristics of these isolates.