Scientia Agricultura Sinica

Characterization of the Regulatory Gene hrd1(t) Involved in Anthocyanin Biosynthesis

LIU Yong-Zhu, LUO Wen-Long, HUANG Cui-Hong, CHEN Li-Kai, WANG Hui, CHEN Zhi-Qiang, GUO Tao

Scientia Agricultura Sinica. 2013, 46(19): 3955-3964. doi:10.3864/j.issn.0578-1752.2013.19.001

Abstract ( 526 )

PDF (1211KB) ( 1235 )

Save

References | Related Articles | Metrics

【Objective】 The objective of this study is to conduct genetic analysis and gene mapping for the purple leaf character of rice germplasm hrd1 (Oryza sativa L. ssp. indica). 【Method】 The regulatory gene hrd1, is a rice germplasm with purple leaf which originated from the hybrids of two green leaf accessions Texianzhan 13 and 02428. Major agronomic traits of hrd1 was firstly investigated, and the segregation ratio of purple and green leaf characters was assayed by using the F1, F2 and BC1F1 populations derived from the crosses of hrd1 and 02428. Fine mapping for the gene contributed to purple leaf character was further conducted by using F2 population, and the candidate gene was identified. 【Result】 The purple character initiates on leaf apex of hrd1 at the 2nd leaf stage and gradually spreads to most parts of the whole plant. At the ripening stage, the agronomic trait of hrd1 was significantly different from the control cultivar (Texianzhan 13). Chlorophyll content was equal between hrd1 and the control, while the anthocyanin content in hrd1 was much higher than that in control. A recessive gene named hrd1(t) controls the purple leaf character in hrd1 according to genetic analysis, and it was mapped to a 32.5 kb region on chromosome 4 between InDel markers HRD10 and HRD21. By sequencing for genes within the mapped region, a single base mutation (A to C) was found in the 3rd exon of LOC_Os04g50660 (encoding a WD and G-beta repeats containing protein), which leads to the predicted amino acid at position 196 converts from lysine in control to threonine in hrd1. 【Conclusion】hrd1(t) encodes a WD40-class transcription factor and may be involved in a regulatory mechanism of pigments.

Biological Characters of Interspecific Hybrid Progenies Between Sesamum indicum L. and Wild Relatives (Sesamum schinzianum Asch, Sesamum radiatum Schum & Thonn)

ZHANG Hai-Yang, MIAO Hong-Mei, ZHANG Ti-De, WEI Li-Bin, LI Chun, WANG Hui-Li, DUAN Ying-Hui, JU Ming

Scientia Agricultura Sinica. 2013, 46(19): 3965-3977. doi:10.3864/j.issn.0578-1752.2013.19.002

Abstract ( 548 )

PDF (740KB) ( 792 )

Save

References | Related Articles | Metrics

【Objective】 In order to explore the compatibility of interspecific hybridization between Sesamum indicum L. and wild species of Sesamum, the genetic characteristics of F1 interspecific hybrids were analyzed. 【Method】Twenty-six cultivar accessions (S. indicum L.) and two wild species, i.e. Congo wild sesame (S. schinzianum Asch) and No. 1 wild sesame (S. radiatum Schum & Thonn) were used as cross parents, the F1 interspecific hybrid progenies were obtained using the immature embryo culture technique. The genetic characters of F1 hybrids were assessed and analyzed using the SSR marker polymorphism and biologic method. 【Result】A total of 2,430 lines of F1 interspecific hybrids were obtained through immature embryo rescue, and the ratio of true hybrid lines reached 95.83%. The crossability frequencies of ‘Congo wild sesame×S. indicum’and ‘No. 1 wild sesame×S. indicum’ cross combinations were 42.31% (direct cross), 11.54% (reciprocal cross), 100% (direct cross), and 19.23% (reciprocal cross), respectively. Pollens of F1 interspecific hybrids presented the partial sterility and high sterility types, and the ratios of F2 seed setting in ‘S. schinzianum×S. indicum’ and ‘S. radiatum ×S. indicum’ crosses were 2.32-2.57 and 0.30-2.45 viable seeds per capsule, respectively. 【Conclusion】The crossability ratio of the cross between S. radiatum and S. indicum is higher than that of the cross between S. schinzianum and S. indicum. F1 hybrids show an obvious superiority for the biological characters such as plant height and root structure, and presented a high resistance to Fusarium wilt disease. Partial F1 lines have the low ratios of viable seed setting.

Comparison of Leaves Proteome and Chlorophyll Fluorescence of Cassava cv. SC8 and Its Tetraploid Mutants

AN Fei-Fei-1, FAN Jie-1, LI Geng-Hu-2, JIAN Chun-Ping-2, LI Kai-Mian-1

Scientia Agricultura Sinica. 2013, 46(19): 3978-3987. doi:10.3864/j.issn.0578-1752.2013.19.003

Abstract ( 565 )

PDF (908KB) ( 816 )

Save

References | Related Articles | Metrics

【Objective】An investigation aimed at a better understanding of the differences in leaves proteins and its relationship with photosynthetic efficiency of cassava diploid and its tetraploid mutants, leaves proteins and chlorophyll fluorescence parameters were analyzed.【Method】Standard chromosome counting and flow cytometric analyses were used to determine the chromosome numbers and ploidy of each taxon, leaves proteins of cassava tetraploid mutants and diploid genotypes were excised and purified from 2D gels. Delta 2D software were used to analyze the differential proteins and MALDI-TOF-TOF-MS/MS were used to identify it. And western blot was used to verify some differential expressed proteins. 95% ethanol extraction method was used to measure the chlorophyll content and imaging-pam was used to determine the fluorescence parameters.【Result】Induced SC8 polyploid mutants were tetraploid, 13 differential expressed protein spots were identified, in which 12 were up-regulated and 1 was down-regulated, and 12 were successfully matched in database. The function of these 12 proteins which up-regulated were associated with carbohydrate and energy metabolism, photosynthesis, antioxidant and protein metabolism, 1 down-regulated protein was not matched in database, in which 46.2% differential expressed proteins were related with photosynthesis, chlorophyll a, chlorophyll b and total chlorophyll in tetraploid mutants were significantly increased, also the fluorescence parameters including Fo, ΦPSII, qP, NPQ and ETR.【Conclusion】Protein expression levels related with carbohydrate and energy metabolism and photosynthesis were up-regulated, chlorophyll content and chlorophyll fluorescence parameters were increased significantly, these indicate that high light-harvesting ability and high photochemical conversion rate in PSII reaction center of cassava tetraploid mutant leaves, then improving photosynthesis efficiency of SC8 tetraploidy mutants.

Variation Laws of Carotenoids Content in Storage Root of Orange-Fleshed Sweetpotato and Its Relationships with Major Economic Traits

HOU Meng, ZHANG Yun-Gang, WANG Xin, TANG Wei, LIU Ya-Ju, TANG Zhong-Hou, JIN Rong, YAN Hui, MA Dai-Fu, LI Qiang

Scientia Agricultura Sinica. 2013, 46(19): 3988-3996. doi:10.3864/j.issn.0578-1752.2013.19.004

Abstract ( 496 )

PDF (604KB) ( 831 )

Save

References | Related Articles | Metrics

【Objective】Accumulation laws of carotenoids content in storage root during development and among varieties and their relationships with major economic traits in orange-fleshed sweetpotato (Ipomoea Batatas (L.) Lam) were studied in present paper.【Method】The dynamics of main economic traits in 15 orange-fleshed sweetpotato varieties on 50, 64, 78, 92, 106, 120, and 134 d after transplanting were investigated, and these traits included the carotenoids content, longest vine length, branches number of vine system, storage roots number, dry matter contents in stem, foliage, petiole and storage roots, fresh and dry weights of storage roots, fresh and dry weights of stem, fresh and dry weights of foliage, fresh and dry weights of aboveground plant, fresh and dry weights of whole plant, and ratios of photosynthate to storage roots, stem, foliage and petiole. The relationship between variations of the carotenoids content and other economic traits during whole developing stage was analyzed. And the relationship between daily growth rates of the carotenoids accumulation and other main economic traits was also analyzed. 【Result】During the whole development, the carotenoids content had three variation types, that is totally leveling, straightly increasing and deviously ascending, and had different responses to the growth of longest vine length, fresh and dry weights of storage roots, photosynthate distributions, and so on. For most of the tested varieties, especially the straightly increasing type in the study, the carotenoids contents had a significant positive correlation with longest vine length, fresh and dry weights of storage roots and ratio of photosynthate to storage roots, and had a significant negative correlation with the ratio of photosynthate to foliage and petiole, however had a least correlation with other traits. Because of the positive correlation between daily growth rates of carotenoids accumulation and fresh and dry weights of storage roots, starch accumulation, soluble sugar accumulation, crude protein accumulation, the carotenoids and dry matter, main nutrient substances accumulated synergistically in storage roots. 【Conclusion】The significant difference and differentiation of carotenoids contents among varieties would take place during development of orange-fleshed sweetpotato, and there were totally leveling, straightly increasing and deviously ascending variation types of carotenoids content because of the synergistical accumulations between carotenoids and dry matter in storage roots among varieties. These variations of carotenoids accumulation had different relationships with main economic traits during development and among varieties in orange-fleshed sweetpotato.

The Possible Effects of Global Warming on Cropping Systems in China Ⅸ. The Risk of High and Low Temperature Disasters for Single and Double Rice and Its Impacts on Rice Yield in the Middle-Lower Yangtze Plain

LI Yong-12, YANG Xiao-Guang-2, YE Qing-23, CHEN Fu-4

Scientia Agricultura Sinica. 2013, 46(19): 3997-4006. doi:10.3864/j.issn.0578-1752.2013.19.005

Abstract ( 554 )

PDF (828KB) ( 1112 )

Save

References | Related Articles | Metrics

【Objective】 In this study, the change of safety planting northern limits of double rice cropping systems and the areas of sensitive regions caused by climate change during 1981 to 2010 and 1951 to 1980 were analyzed in the Middle-Lower Yangtze Plain. Also the risk of high and low temperature hazards during the growing season of single rice and double rice and its impacts on rice yields in the sensitive planting regions for rice safety planting (SPR) were compared and discussed.【Method】SPR were determined based on the indices of regionalization for cropping systems and agro-meteorology methods. Then according to the indices of high temperature and low temperature hazards for rice, the impacts of these two disasters on rice yields in SPR were analyzed by Oryza2000 model.【Result】Compared with 1951 to 1980, the areas of SPR in the Middle-Lower Yangtze Plain increased by 11.5×104 km2. The high and low temperature disasters with the largest frequency for early, late, and single rice are low temperature disaster during seedling bed period, low temperature disaster during filling and ripening period, and high temperature disaster during booting and heading period, respectively. However, the disasters with the greatest impacts on crop yield for early, late, and single rice are low temperature disaster during seedling bed period, low temperature disaster during booting and heading period, and high temperature disaster during filling and ripening period. The frequency of mostly high temperature disaster during different growing periods for early, late and single rice increased, and the frequency of mostly low temperature disaster decreased.【Conclusion】Under the background of climate warming, the obvious changes for safety planting area of double rice cropping systems in the Middle-Lower Yangtze Plain were found. There were significant differences for the risks of high and low temperature disaster and its impacts on rice yields in the areas of SPR during the growing season of single and double rice.

Effect of Root in Different Soil Layers on Plant Growth and Yield Formation After Anthesis in Summer Maize

WANG Fei-Fei-1, ZHANG Shan-Ping-1, SHAO Li-Jie-1, LI Geng-1, CHEN Xiao-Lu-1, LIU Peng-1, ZHAO Bing-Qiang-2, DONG Shu-Ting-1, ZHANG Ji-Wang-1, ZHAO Bin-1

Scientia Agricultura Sinica. 2013, 46(19): 4007-4017. doi:10.3864/j.issn.0578-1752.2013.19.006

Abstract ( 475 )

PDF (602KB) ( 1022 )

Save

References | Related Articles | Metrics

【Objective】This study was conducted to evaluate the regulating effects of roots in different soil layers on plant growth after anthesis and yield formation in summer maize，aimed to provide theoretical supports for building high efficient root systems of maize and then increase grain yield of maize.【Method】Two high yield summer maize varieties, Zhengdan 958 (ZD) and Denghai 661 (DH), were used as experimental materials, and they were planted in soil columns. Three treatments (without cutting the roots, CK; cutting maize roots at 40 cm below the surface at anthesis, T-40; cutting roots at 80 cm below the surface at anthesis) were designed to evaluate the regulating effects of summer maize roots in different soil layers on shoot growth and yield formation.【Result】 The regulation of upper roots (0-40 cm) to nitrogen uptake and translocation was most significantly. While losing function of deep roots (below 40 cm) reduced nitrogen absorption capacity, and accelerated the transportation from nutritive organs to grain kernels. Deep roots below 40 cm had significant effects on leaves staying green and photosynthetic performance. Cutting deeper roots at anthesis significantly decreased green leaf area per plant, chlorophyll content, activity of SOD and Pn, and increased the content of MDA, shortened the duration of high photosynthesis and reduced biomass of plant and grain yield significantly. Intermediate roots (40-80 cm) had notable influence on grain numbers of per ear and grain weight; however, deeper roots had more significant effects on grain weight than grain numbers per ear.【Conclusion】Cutting upper roots (0-40 cm) reduced maize yield significantly. Intermediate roots had significant influences on grain numbers per ear and grain weight; deeper roots had significant effects on grain weight than grain numbers per ear. In high-yielding cultivation, keeping deep root actively can delay leaf senescence, enhance photosynthetic performance and absorption of nitrogen, and increase grain yield.

Effects of Raised-Bed Planting and High Plant Density on Yield-Increasing of Cotton in the Yellow River Basin

LU He-Quan, LI Zhen-Huai, DONG He-Zhong, LI Wei-Jiang, TANG Wei, ZHANG Dong-Mei

Scientia Agricultura Sinica. 2013, 46(19): 4018-4026. doi:10.3864/j.issn.0578-1752.2013.19.007

Abstract ( 426 )

PDF (675KB) ( 708 )

Save

References | Related Articles | Metrics

【Objective】 Raised-bed planting and plant density have been widely studied as a single practice in cotton production, but their combination to approach better yields and benefits was less studied. Since effective combination of raised-bed planting and plant density may further increase cotton yield, it is very important to conduct profound studies on interaction of plant density and raised-bed planting.【Method】A two-year field experiment was carried out to evaluate the effects of raised-bed planting and plant density on earliness, leaf area index, abscission rate of squares and young bolls, yield and yield components. A split-plot design with three replicates was used for the study. The main plots comprised two planting patterns (raised-bed planting and flat planting), while planting densities (3, 6 and 9 plants/m2) constituted the subplots.【Result】Significant interaction was detected between planting pattern and plant density on cotton yield. Flat planting produced the highest cotton yield at medium plant density (6 plants/m2), while raised-bed planting produced the highest and lowest cotton yield at 9 plants/m2 and 3-6 plants/m2, respectively. Raised-bed planting at 9 plants/m2 was 13.6% higher than traditional flat planting at 6 plants/m2. Both planting pattern and plant density significantly affected yield components. Boll weight and earliness under raised-bed planting were higher than those under the flat planting, and the number of bolls/m2 was increased as plant density rose. Raised-bed planting significantly increased biological yield, ratio of seed cotton to stalk and leaf area index, but decreased the rate of rotted bolls and abscission of squares and bolls.【Conclusion】Planting pattern and plant density affected biological yield, harvest index and yield components individually or interactively, thus resulting in a significant effect on economic yield. It is thus suggested that raised-bed planting at high plant density might be a promising alternative to further improve cotton yield in Yellow River basin.

Study on Correlation Between Ammonia Volatilization and Nitrogen Metabolism During the Tobacco Leaves Senescence

WU Yun-Jie, YANG Tie-Zhao, ZHANG Xiao-Quan, LI Fei, LI Li-Hua

Scientia Agricultura Sinica. 2013, 46(19): 4027-4034. doi:10.3864/j.issn.0578-1752.2013.19.008

Abstract ( 498 )

PDF (520KB) ( 666 )

Save

References | Related Articles | Metrics

【Objective】The objective of this experiment is to study the difference of different N efficiency varieties of flue-cured tobacco leaf senescence ammonia volatilization amount in the process, reveal tobacco varieties N transport law, so as to provide a basis for nitrogen resistant variety breeding.【Method】Using ammonia collection device was used to determine the amount of ammonia volatilization of tobacco. At the same time, leaves NH4+ concentration, total N and soluble protein content, N metabolism-related enzyme activity, and apoplast related indicators were measured.【Result】Tobacco amount of ammonia volatilization showed a trend of first increase and then decrease, the maximum at leaf age of 60 d. The amount in varieties Zhongyan90, K326 and NC89, respectively, reached (16.39±1.08) μg•m-2•h-1, (9.92±1.04) μg•m-2•h-1, and (4.56±0.63) μg•m-2•h-1, respectively, 3.87, 2.41 and 2.56 times of the leaf age 40 d ammonia volatilization, and the difference among the varieties was significant. The amount of ammonia volatilization and glutamine synthetase (GS) activity were significantly and negatively correlated, and very significantly and positively correlated with the glutamate dehydrogenase (GDH) activity, apoplastic NH4+ concentration and pH, ammonia compensation point, while very significantly and negatively correlated, with the content of soluble protein and nitrate reductase (NR) activity, They showed a quadratic curve with the leaves NH4+ concentration, and the correlation was extremely significant, and are subject to total N degradation of indirect control. 【Conclusion】 There is a difference among different nitrogen efficient varieties in nitrogen reassimilation and transfer ability，and it is associated with tobacco leaf N metabolism characteristics. During the tobacco senescence, varieties of low N use efficiency, N absorption and assimilation capacity is weak, the transfer capacity, ammonia volatilization amount is big. Through volatilization of ammonia outside the body, increased the transfer of NH4+, reduced the accumulation of ammonia pollution, so it is an important method for plant N metabolic regulation, which can be used as an evaluation of index of a variety nitrogen efficiency.

Isolation and Expression Patterns of Rice WRKY80 Transcription Regulatory Protein Gene

PENG Xi-Xu, TANG Xin-Ke, ZHOU Ping-Lan, HU Yao-Jun, DENG Xiao-Bo, WANG Hai-Hua

Scientia Agricultura Sinica. 2013, 46(19): 4035-4043. doi:10.3864/j.issn.0578-1752.2013.19.009

Abstract ( 503 )

PDF (588KB) ( 889 )

Save

References | Related Articles | Metrics

【Objective】 The objective of this study is to isolate rice WRKY80, to analyze the characteristics of its coding sequence and to investigate its expression patterns in different organs and under pathogen inoculation and hormone application, thus providing a basis for its function identification. 【Method】Specific primer sequences were designed according to the annotated gene Loc_Os03g63810 released in rice genome database. RT-PCR was used to amplify WRKY80 cDNA sequence from RNA pools generated from methyl jasmonate (MeJA)-treated rice leaves. Bioinformatical tools were employed to analyze its deduced protein sequence and cis-elements in its promoter. Northern blot or real-time fluorescence quantification PCR was used to investigate its expression patterns. 【Result】 The obtained cDNA sequence of WRKY80 was 1 392 bp in length, containing an entire open reading frame of 1 164 bp, encoding a polypeptide of 387 amino acid residues consisting of one classic conserved WRKY domain with a zinc finger motif of C2H2, belonging to the WRKY subgroup Ⅱ. WRKY80 possessed an acidic C terminus with consecutive 6 glutamines and 8 threonines, an acidic region possibly responsible for transcription activating activity, and was predicted to be localized in nucleus. WRKY80 shared high identity at the amino acid level with those from monocotyledons Zea mays and Sorghum bicolor. WRKY80 was constitutively expressed in all tested organs. The transcript abundance was relatively higher in leaves, roots and panicles, next was in flowers, and less was in stems and grains. WRKY80 expression was higher in mature leaves and roots than in young leaves and roots, respectively, indicating a developmental stage-related feature. It was rapidly induced by inoculation with Magnaporthe oryzae and Rhizoctonia solani, and also by application of exogenous MeJA and ethephon, whereas salicylic acid exerted no effects on its expression. Consistent with the expression profiles was the prediction result of cis-elements in its promoter. 【Conclusion】WRKY80 possesses structure characteristics as a putative transcription factor. These findings suggest that it may be involved in defense response to the fungal pathogens and also in development regulation by jasmonic acid/ethylene-dependent signaling pathway.

Identification of Cercospora Species Associated with Maize Gray Leaf Spot in China

LIU Qing-Kui-1, QIN Zi-Hui-1, ZHANG Xiao-Li-1, JIANG Kai-1, CHEN Mao-Gong-1, WU Xiao-Fei-1, HE Yue-Qiu-2, WANG Gui-Qing-3, JIN Qi-Ming-4, WANG Xiao-Ming-1

Scientia Agricultura Sinica. 2013, 46(19): 4044-4057. doi:10.3864/j.issn.0578-1752.2013.19.010

Abstract ( 525 )

PDF (1150KB) ( 979 )

Save

References | Related Articles | Metrics

【Objective】 The objective of this study is to understand the Cercospora species causing maize gray leaf spot (GLS) in China. 【Method】 The samples of GLS were widely collected from maize producing areas and strains were isolated using single-spore isolation technique. The causal agents were identified based on fungal morphology, culture and molecular characters. 【Result】One hundred and thirty-six strains were isolated from samples collected in Heilongjiang, Jilin, Liaoning, Inner Mongolia, Shandong, Yunnan and Hubei provinces. Of them 65 strains were identified as C. zeae-maydis which found in northern provinces as well as in early years in Yunnan. Seventy-one were C. zeina only occurred in Yunnan and Hubei provinces. C. sorghi var. maydis, which was reported in China, was not detected in the strains. 【Conclusion】 In China, there are two Cercospora species causing GLS, which are C. zeae-maydis and C. zeina. The former is found in the northern China, including Heilongjiang, Jilin, Liaoning, Inner Mongolia and Shandong provinces, and in the strains collected in Yunnan before 2008, and the later was distributed in southwest China, such as Yunnan and Hubei provinces. C. zeina is firstly reported as a causal agent of gray leaf spot on maize in China.

Analysis on Mating Type and Parasitic Fitness Diversity in Sexual Hybridization Offsprings of Setosphaeria turcica

GUO Li-Yuan-1, JIA Hui-1, CAO Zhi-Yan-1, GU Shou-Qin-1, SUN Shu-Qin-2, DONG Jin-Gao-1

Scientia Agricultura Sinica. 2013, 46(19): 4058-4065. doi:10.3864/j.issn.0578-1752.2013.19.011

Abstract ( 471 )

PDF (597KB) ( 579 )

Save

References | Related Articles | Metrics

【Objective】The objective of this study is to analyze the diversity of mating type and pathogenicity in sexual hybridization offsprings of Setosphaeria turcica and investigate the relationship between sexual hybridization and variation of S. turcica.【Method】Using isolates 01-12 and 01-15 of S. turcica as parents, the sexual hybridization F1 generations were obtained by artificial induction, and F2 generation isolates were got by the same method when isolates 40 and 42 coming from F1 generation were used as parents. The mating type and parasitic fitness of sexual hybridization offsprings were tested with Huangzaosi. The toxin of different pathogenic isolates was analyzed by capillary electrophoresis. 【Result】Two sexual generations were induced continuously. Seventy-nine sexual hybridization F1 and thirty-two F2 isolates were obtained in this experiment. The mating types were A, a, Aa and neutral isolates, which appeared obvious diversity, but the ratio of A and a in F1 generations was far away from 1:1. The result of parasitic fitness showed that F1 and F2 isolates generated diversity. The percentages of strong parasitic fitness and feeble parasitic fitness in F1 generations were 30.00% and 50.00%, respectively, and those in F2 generations were 21.87% and 31.25%, respectively. The results of capillary electrophoresis suggested that the toxin content of stronger pathogenic isolates were higher than that of lower pathogenic isolates. 【Conclusion】 The sexual hybridization is one of the chief elements resulting in mat type and pathogenic diversity. The toxin content of an isolate is positively correlated with its pathogenicity.

Bioinformatics of Downy Mildew Resistance to Cucumber Candidate Genes and Specific Expression in Organise

LIU Da-Jun-12, QIN Zhi-Wei-1, ZHOU Xiu-Yan-1, WU Tao-1, XIN Ming-1

Scientia Agricultura Sinica. 2013, 46(19): 4066-4074. doi:10.3864/j.issn.0578-1752.2013.19.012

Abstract ( 424 )

PDF (857KB) ( 1066 )

Save

References | Related Articles | Metrics

【Objective】The objective of this study is to investigate the downy mildew resistance genes in cucumber, and to clarify its molecular mechanism. 【Method】Cucumber candidate genes with resistance against downy mildew were identified from the cucumber genome database and blast protein sequences in Arabidopsis thaliana, and melon downy mildew resistance genes. Cucumber candidate genes were analyzed by bioinformatics way. Inbred line M801-3-1 with downy mildew resistance was used as test materials. Expression patterns of the genes were monitored by RT-PCR technique in cucumber leaf.【Result】One hundred and eighty-seven cucumber candidate genes as resistances against downy mildew were identified. Through bioinformatics analysis, the location of candidate genes in chromosomes and characteristics of arrangement were confirmed, and sequence comparability characteristics and relationship of system evolution were analyzed. The results of RT-PCR test indicated that most of the tested genes expressed either sprayed with the pathogen or water. The results of Florescent real-time quantitative RT-PCR test indicated that only Csa001907 and Csa002921 showed significant reduction in the leaves sprayed with the pathogen. 【Conclusion】 In the cucumber genome, there are 185 genes homologous A. thaliana downy mildew resistance genes, and there are 2 genes homologous melon resistance to downy mildew genes At1 and At2. Through clustering analysis these genes can be divided into 6 categories. Csa001907 and Csa002921 are most likely R gene of cucumber downy mildew resistance. R genes may be stablly expressed in leaves, R genes original expressions are interfered that may be the reasons of cucumber downy mildew infections.

Identification of Viruses from Potato Planted in Winter in Guangxi by Small RNA Deep Sequencing

SONG Jing-Jing-1, MENG Jiao-Rong-12, ZOU Cheng-Wu-3, LI Pu-3, WANG Zhi-Qiang-2, CHEN Bao-Shan-23

Scientia Agricultura Sinica. 2013, 46(19): 4075-4081. doi:10.3864/j.issn.0578-1752.2013.19.013

Abstract ( 517 )

PDF (586KB) ( 773 )

Save

References | Related Articles | Metrics

【Objective】The objective of this study is to identify viruses infecting potato planted in winter in Guangxi for establishing a future healthy potato seed program and better disease control in the field. 【Method】One hundred and nine samples with viral disease-like symptoms were collected from potato plants in the fields in 2012 and subject to initial ELISA screening before they were pooled and analyzed by small RNA deep sequencing. Viruses identified by small RNA sequencing were validated by virus-specific RT-PCR from selected groups of samples.【Result】Potato leafroll virus (PLRV), Potato virus A (PVA), Potato virus H (PVH), Potato virus M (PVM), Potato virus S (PVS), Potato virus Y (PVY), and Potato spindle tuber viroid (PSTVd) were detected in the samples and PVS was found to have a rich genetic diversity.【Conclusion】Potato planted in winter in Guangxi were infected with many viruses including two viruses and a viroid that had not been reported in the region before. Thus, a virus-free healthy potato seed program is needed in urgency.

Screening of Low Temperature Maize Stalk Decomposition Microorganism

SA Ru-La, GAO Ju-Lin, YU Xiao-Fang, HU Shu-Ping

Scientia Agricultura Sinica. 2013, 46(19): 4082-4090. doi:10.3864/j.issn.0578-1752.2013.19.014

Abstract ( 496 )

PDF (658KB) ( 904 )

Save

References | Related Articles | Metrics

【Objective】 For the purpose of accelerating the northern region maize straw degradation speed, a research was conducted to screen microorganism which has a good ability to degradate maize straw under the conditions of low temperature. 【Method】 In this experiment, materials rich in cellulose were used as bacteria sources, through preliminary screening by filter-paper disintegration indicator, enzyme activity and straw degradation rate re-screening, the maize straw degradation strains were selected, then its composition was analyzed. 【Result】 Using this method, two cellulose-degrading microflora (designated as No.1 and No.8) capable of effectively degrading maize straw was enriched from plateau rotted sawdust successfully. The microflora No.1 and No.8 were inoculated in the medium with maize straw as a sole carbon and energy source. The degradation rate of maize straw were 30.21% and 32.21% after 15 days cultivation under 15℃. Two groups of composite microbial systems were composed of fungi and bacteria.No.1 strains of fungus were Trichoderma, and No.8 strains fungus were Penicillium. Two groups of composite microbial system was mainly composed of Clostridium bacteria, Bacillus and oxalic acid bacillus bacteria. 【Conclusion】 Screening of the strains under low temperature (15℃) could degrade the maize straw under laboratory conditions, and the microbial system was mainly comprised of Trichoderma, Penicillium, Clostridium, Bacillus and Herbaspirillum.

Analysis on the Soil and Water Conservation Benefits of Four Bunds at Edges of Sloping Land in Purple Hilly Area

WANG San-Shu-1, LIU De-Zhong-2, SHI Dong-Mei-1, HUANG Xian-Zhi-3, TANG Xue-Wen-4, LI Ye-Xin-1, GAN Xue-Lian-5

Scientia Agricultura Sinica. 2013, 46(19): 4091-4100. doi:10.3864/j.issn.0578-1752.2013.19.015

Abstract ( 506 )

PDF (643KB) ( 1116 )

Save

References | Related Articles | Metrics

【Objective】 The article aimed to study the soil and water conservation benefits of four bunds at edges of sloping land in purple hilly area. 【Method】 A systematic analysis of the soil and water conservation benefits and its influencing factors of various bunds was made through such comprehensive research approaches as soil physical and mechanical properties analysis and so on. 【Result】 Soil total porosity of different bunds planted with vegetation were shown as mulberry＞prickly ash＞alfalfa＞natural grass; a similar varying trends of initial infiltration rate, final infiltration rate and mean infiltration rate for each kind of bund existed, which showing a trend of mulberry＞prickly ash＞alfalfa＞natural grass. Soil available water storage of all bunds was obviously different (P＜0.05) from natural grass, which presented as the bund planted with tree＞grass＞natural grass. During the process of water storage for all bunds, the higher the soil non-capillary porosity and soil total porosity was, the better the soil infiltration capacity could be. The larger the soil bulk density was, the worse soil infiltration capability and soil perviousness would be, which leading to larger unavailable soil reservoir, and also making it is difficult for crops on sloping lands to absorb soil water. Soil shear strength of all bunds was in the order as alfalfa (0.38 kg•cm-2)＞prickly ash (0.25 kg•cm-2)＞mulberry (0.22 kg•cm-2)＞natural grass (0.18 kg•cm-2), and internal friction angle of the bunds of prickly ash was the biggest（20.76°）among these bunds. The internal friction angle of all bunds had a significant negative correlation with fractal dimension of particle size distribution, initial water content of soil, while it had a significant positive correlation with fractal dimension of aggregate size distribution. However, soil cohesion and shear strength had a significant negative correlation with fractal dimension of particle size distribution and a significant positive correlation with soil dispersion, but soil cohesion and shear strength did not correlate significantly with fractal dimension of aggregate size distribution. 【Conclusion】 All bunds in purple hilly area improved the available soil reservoir by the way of improving soil physical properties such as soil pore structure and so on, which preventing sloping land from the damage of local seasonal drought. Moreover, the bunds also enhanced the soil shear strength and the ability of resistance to rainfall and runoff erosion, which obviously ensuring the stable productivity of sloping land in purple hilly area

Analysis of Organic Acid Accumulation Characteristics and Organic Acid-Metabolizing Enzyme Activities of Chinese Dwarf Cherry (Cerasus humilis Bunge) Fruit

WANG Peng-Fei-1, XUE Xiao-Fang-12, MU Xiao-Peng-1, ZHANG Jian-Cheng-1, CAO Qin-1, DU Jun-Jie-1

Scientia Agricultura Sinica. 2013, 46(19): 4101-4109. doi:10.3864/j.issn.0578-1752.2013.19.016

Abstract ( 455 )

PDF (616KB) ( 1053 )

Save

References | Related Articles | Metrics

【Objective】 The accumulation characteristics of main organic acid and activities of acid-related enzymes between two cultivars of Chinese dwarf cherry with different acidities were compared. 【Method】 Using the method of ultra performance liquid chromatograph (UPLC), the contents of total organic acids, malic acid and citric acid, as well as the activities of organic acid-metabolizing enzymes were analyzed during the fruit development of 6-year-old Chinese dwarf cherry ‘Nongda 3’ and ‘Nongda 4’. 【Result】Malic acid and citric acid of these two varieties accumulated mainly in the late period of fruit development, but their accumulation rates were quite different. Because of the high NADP-ME activity and the low NAD-MDH and PEPC activities, there was only a small amount of malic acid accumulation in the early period of fruit development. During the late period, NADP-ME activity decreased rapidly and NAD-MDH activity and PEPC activity began increasing, which promoted a massive accumulation of malic acid. The sudden increase of NADP-ME activity and the decline of NAD-MDH activity and PEPC activity caused the degradation of mailc acid at the ripening stage. Before the ripening stage(18-19 weeks after anthesis), NAD-MDH activity of ‘Nongda 4’ was higher than the activity of ‘Nongda 3’ , while NADP-ME activity of ‘Nongda 4’ was lower. As a result, the content of malic acid of ‘Nongda 4’ was higher than the content of ‘Nongda 3’. The content of citric acid of ‘Nongda 3’ was higher (17-19 weeks after anthesis) because its CS activity was higher at the ripening stage.【Conclusion】The late period of fruit development is a critical period for the accumulation of malic acid and citric acid. The difference in malic acid accumulation is mainly caused by the coordination change of NAD-MDH activity and NADP-ME activity, while the difference in the accumulation of citric acid is mainly affected by the change of CS activity.

Fruit Sugar and Acid Content, Variation at Different Fruit Development Stages and Their Relationship with Leaf Soluble Sugar Content of Blueberry

LIU You-Chun-12, TAO Cheng-Guang-3, WEI Yong-Xiang-2, LIU Cheng-2, WANG Xing-Dong-2, LIU Wei-Sheng-2, YANG Yan-Min-2

Scientia Agricultura Sinica. 2013, 46(19): 4110-4118. doi:10.3864/j.issn.0578-1752.2013.19.017

Abstract ( 563 )

PDF (534KB) ( 1377 )

Save

References | Related Articles | Metrics

【Objective】An experiment was conducted to study the characters of sugar and acid content and analyze the relationships of sugar content in fruits and leaves during fruit development, thus providing a theoretical basis for metabolic mechanism of sugar and acid and quality regulation, in blueberry.【Method】Five cultivars of three taxonomic types , including high bush blueberry, e.g. ‘Spartan’ and ‘Jersey’, half-high bush blueberry, e.g. ‘North country’ and ‘North blue’ and low bush blueberry, e.g. ‘Blomidon’ were used to investigate the seasonal variation of sugar and acid content in fruits and leaves at different fruit development stages by high performance liquid chromatography (HPLC). 【Result】The results indicated that the average content of total sugar was 102.04 mg•g-1 FW, the highest and lowest of total sugar content existed in ‘Spartan’ and ‘North country’, respectively. Glucose and fructose content increased during fruit maturation and the contents of them accounted for 97.90%-99.47% of total sugar content in mature fruit, the ratio of them was 1:1, whereas the sucrose and sorbitol contents decreased constantly from a low level during fruit maturation into traces of them in matured fruit. The average content of total acid was 7.10 mg•g-1 FW, in tested high bush blueberry and half-high bush, citric acid was the major organic acid, accounted for 76.94% of total acid in mature fruit which increased at early stage, and decreased quickly till fruit maturity, quinic acid and malic acid contents decreased gradually. There was a similar change trend and component in both low bush cultivars ‘Blomidon’ and half-high bush cultivar ‘North country’, with quinic acid being the main acid and it presented a decline tendency during the fruit development stage, the content was higher than other cultivars in matured fruit, citric acid and tartaric were the minor components; Sorbitol accounted for 67.28% of total sugar in leaves, and the content reached top at 42 d after full bloom (around 15 d before harvest) , then decreased quickly.【Conclusion】The component characters of organic acid in ‘Blomidon’ and ‘North country’ were obviously distinguished from high bush and half-high bush blueberry. Sorbitol was the main soluble sugars in leaves. The stage of around 15 days before harvest was the critical period of fruit expansion growth and sugar accumulation.

Differential Genes Expression in Tea Plant (Cameilla sinensis L.) Induced by Ectropis oblique Feeding Based on cDNA-AFLP

CAO Shi-Xian, CHENG Xi, JIANG Zheng-Zhong, SHENG Liang, SHANG Guan-Ming-Zhu, DENG Wei-Wei, WEI Chao-Ling

Scientia Agricultura Sinica. 2013, 46(19): 4119-4130. doi:10.3864/j.issn.0578-1752.2013.19.018

Abstract ( 431 )

PDF (817KB) ( 616 )

Save

References | Related Articles | Metrics

【Objective】 The objective of this study is to screen the defense genes in tea plant (Camellia sinensis L.) induced by tea looper (Ectropis oblique).【Method】Tea leaves fed by the looper were analyzed by cDNA-AFLP(cDNA-amplified fragment length polymorphism). Transcript-derived fragments (TDF) were screened and confirmed. After that, bioinformatics analysis was followed. And the expression patterns of the differential genes were performed by qRT-PCR.【Result】The results showed that 134 EST(expressed sequence tags) were obtained by sequencing and identifying from the selected 231 TDFs. Among them, 81 TDFs were up-regulated, and 53 were down-regulated, which accounted for 60.4% and 39.6% of the obtained fragments, respectively. According to BLASTx result of TDFs, a large group (23.1%) of these genes shared high homology with genes involved in metabolism, 9.0% genes with functions related to photosynthesis and energy, 8.2% genes with functions related to protein synthesis and storage, signal transduction, 5.2% genes with functions related to disease/defense. But only few genes involved in cell growth and structure, transcription factor and transporters and the ratios were 1.5%, 2.2%, and 3.0%, respectively. Moreover, sequences with unknown proteins occupied 6.7%; and 20.1% sequences with no similarity against the database. TDF-21F1, TDF-22D, TDF-27L3 and TDF-28F were confirmed by qRT-PCR analysis, further result indicated that the expression of the defense genes responsive to Ectropis oblique play significant regulation roles in adapting to negative environment for tea plant.【Conclusion】Using cDNA-AFLP method to analyze Ectropis oblique feeding tea plant and get the TDFs, it could supply valuable information to the study of the molecular mechanism between tea and pest.

Construction and Application of Flavonoids Characteristic Constituents HPLC Fingerprints of Fengjie Navel Orange (Citrus sinensis Osbeck)

LIU Shi-Yao

Scientia Agricultura Sinica. 2013, 46(19): 4131-4148. doi:10.3864/j.issn.0578-1752.2013.19.019

Abstract ( 495 )

PDF (1704KB) ( 646 )

Save

References | Related Articles | Metrics

【Objective】 This study constructed the total flavonoids characteristic constituents HPLC fingerprints of Fengjie navel orange (Citrus sinensis Osbeck ) came from its original birthplace. And authenticity of the 5 popular commercial sweet orange were tested compared to its standard HPLC fingerprints in order to provide a scientific evidence for quality evaluation and genuine identification of the citrus fruit. 【Method】 By High Performance Liquid Chromatography-Photo-Diode Array Detector (HPLC-PDA), the study carried out advancing and HPLC detecting of the total flavonoids characteristic constituents in Fengjie navel orange samples from 14 main different producing places, then the signal acquiring and the characteristic constituents peaks distinguishing was performed by the PDA and Shimadzu LC solution Ver 1.0, respectively. The hesperidin and naringin contents in peel, flesh and juice of the samples were detected by external standard method. At last the total flavonoids characteristic constituents HPLC fingerprints from different parts of the samples were constructed and their similarity were calculated and analysed by the professional similarity evaluation software including validation study. 【Result】 Results showed that hesperidin content range in the peel, flesh and juice of the samples was 1.67%-3.76%, 0.69%-1.67% and 0.022-0.318 mg•(10mL)-1, the mean value was 2.87%, 1.25% and 0.1215 mg•(10mL)-1, respectively. The naringin content range of fruits peel was 0.01%-0.15%, and its average value was 0.08%. However, they were not detected in their flesh and juice. The chromatographic peaks shape of total flavonoids in peel and flesh of different samples was generally coherent. And their common peaks were well matched and the number was 35 and 35 irespectively. Peaks distributing difference of the constructed characteristic chromatographic fingerprint of peel and flesh was obviously different. The relative content data of their common peaks was stable with reference of hesperidin peak. The similarity of samples calculated by the vector angel cosine all was above 0.990 with their characteristic HPLC fingerprint. So both of them could be used to its peculiar evaluate and genuine identification. But there was an obvious difference among the chromatographic fingerprints of the Fengjie navel orange juice and low peaks-matching rate, so the samples’ juice total flavonoids characteristic fingerprint was unsuitable for utility. 【Conclusion】 This method is accurate, reliable and well reproducible, and it is suitable for peculiar identification of Fengjie navel orange fruits well known in China and quality evaluation of the other domestic citrus cultivars.

Texture and Rheological Properties of Camembert Cheeses During Ripening

YU Hua-Ning-12, WANG Jia-Yue-3, HANG Feng-1, LIU Zhen-Min-1, LI Yun-Fei-2, GUO Ben-Heng-1, MEI Jun-2, XIA Yong-Jun-1, HOU Jian-Ping-1

Scientia Agricultura Sinica. 2013, 46(19): 4149-4156. doi:10.3864/j.issn.0578-1752.2013.19.020

Abstract ( 568 )

PDF (568KB) ( 618 )

Save

References | Related Articles | Metrics

【Objective】 Changes of textural and rheological properties of camembert cheeses were studied during their ripening. 【Method】 Textural properties of different parts of camembert cheeses, including hardness, adhesiveness, springiness, cohesiveness, chewiness and gumminess, were analyzed using Texture Profile Analysis method. Rheological properties including elastic modulus (G’), viscous modulus (G’’) and loss angle (δ), were measured by rheometer and the results were statistically analyzed by SAS software. 【Result】 Water activity and pH of camembert cheeses were significantly affected by ripening time (P＜0.05), but the effect of moisture content was not significant (P＞0.05). During ripening, textural and rheological properties of inner parts of camembert cheeses were significantly different from that of the rind. Hardness, chewiness and gumminess of inner parts decreased with ripening time, but adhesiveness increased. Hardness of the rind increased first but then decreased with ripening time, chewiness and gumminess decreased, but adhesiveness increased. The G’ and G’’ were significantly different among different parts of cheeses (P＜0.05), and the G’ and G’’ of inner parts were bigger than those of the rind. The G’ and G’’ of inner parts increased first but then decreased with ripening time. 【Conclusion】 The textural and rheological properties of camembert cheeses during ripening were mostly correlated with ripening time.

Effects of GSPs and VE on Growth Performance, Serum Redox Status and Hepatic Oxidative Damage in Piglets Under Oxidative Stress

ZHAO Jiao, ZHOU Zhao-Hong, LIANG Xiao-Fang, MAO Xiang-Bing, CHEN Dai-Wen, YU Bing

Scientia Agricultura Sinica. 2013, 46(19): 4157-4164. doi:10.3864/j.issn.0578-1752.2013.19.021

Abstract ( 525 )

PDF (630KB) ( 807 )

Save

References | Related Articles | Metrics

【Objective】 The aim of this study was to investigate the effects of dietary grape seed procyanidins (GSPs) or vitamin E (VE) on growth performance, serum redox status and liver oxidative damage in piglets under oxidative stress. 【Method】 Twenty-four weaned piglets (L×Y) at 28 d of age were allotted into 4 groups with 6 replicates per group and 1 piglet per replicate. Piglets in NC group or Diquat group were fed with basal diet, and those in GSPs+Diquat group or VE+Diquat group were fed with basal diets supplemented with 100 mg•kg-1 GSPs or 50 mg•kg-1 VE, respectively. On d 10, all the piglets in Diquat, GSPs+Diquat and VE+Diquat groups were injected intraperitoneally with Diquat (10 mg•kg-1), and those in NC group were injected with the same amount of sterile saline. The experiment lasted for 17 days. 【Result】 The results showed that Diquat injection caused the reduction of growth performance, anti-oxidant capacities of serum and liver, activities of hepatic ALT and AST(P＜0.05), while increased serum ALT and AST activities (P＜0.05). 100 mg•kg-1 GSPs or 50 mg•kg-1 VE supplementation improved serum GSH-px activity, capacity of anti-superoxide anion as well as hepatic ALT and AST activities (P＜0.05), and decreased ALT and AST activities and MDA content in serum (P＜0.05). Furthermore, GSPs also significantly enhanced serum SOD activity and anti-hydroxyl radical capacity, improved hepatic T-AOC and capacities of anti-hydroxyl radical, and reduced MDA content in liver (P＜0.05). 【Conclusion】Dietary supplementation of 100 mg•kg-1 of GSPs or 50 mg•kg-1 of VE can suppress the oxidative stress caused by Diquat injection in piglets, and GSPs exert a better antioxidant capacity in serum and liver.

Effects of Restricted Access Time to Pasture Combined with Indoor Feeding on Growth Performance and Feed Intake of Ujumuqin Lambs

ZHANG Xiao-Qing-12, LUO Hai-Ling-1, ZHANG Ying-Jun-1, WANG Shuo-1

Scientia Agricultura Sinica. 2013, 46(19): 4165-4172. doi:10.3864/j.issn.0578-1752.2013.19.022

Abstract ( 440 )

PDF (631KB) ( 649 )

Save

References | Related Articles | Metrics

【Objective】This study was conducted to investigate the effects of restricted access time to pasture combined with indoor feeding on growth performance and feed intake of Ujumuqin lambs. 【Method】Thirty castrated male Ujumuqin lambs were randomly assigned into five equal groups with similar metabolic energy diet: (i) alone feeding indoor (0H; control), (ii) 2-h access to pasture (2H), (iii) 4-h access to pasture (4H), (iv) 8-h access to pasture (8H), and (v) full-time access to pasture (12H). Lambs were raised for 102 days, coinciding with a 15-d feed adaptation period and 87-d experimental periods. Body weight, height and length, and heart girth of the lambs were measured before eating in the morning (about 06:00 am) from last of July to September, once a month. The pasture intake was estimated using the n-alkane method in the middle of each month from July to September. 【Result】The restrictions at pasture did not significantly (P＞0.05) affect the amounts of body length and height, and heart girth of the lambs, but had significant (P＜0.05) effects on the ratios of length/height and chest/length. The ratios of length/height in the 8H and 12H groups were higher (P=0.05) compared to the 0H group. The ratios of chest/length in 0H, 2H and 4H groups were higher (P＜0.05) than the 12H group, respectively. No differences were found in final body weight, total weight gain, average daily weight gain (ADG), and total feed intake of lambs among the five groups (P＞0.05). In July, the weight gain significantly decreased (P＜0.01) as the grazing time increased. The gain of lambs of 12H group decreased by 101, 84, 69, and 38 g•d-1 (P＜0.01) as compared to the lambs of 0H, 2H, 4H, and 8H groups, respectively. The gain of grazing 2 and 4 h groups did not differ (P＞0.05) from the 0H group. In August, the maximum gain of lambs was observed in all groups. The lambs imposed with limited pasture access time of 4, 8, and 12 h had much higher weight gain (P=0.045) than the lambs fed indoor or allocated 2 h access to pasture. In September, the gain of lambs in the 0H group was significantly higher (P＜0.05) than in the other groups, and there was no significant difference (P＞0.05) between the latter four groups. As the time at pasture increased, the pasture intake was significantly increased (P＜0.001), but the supplementation intake had a decline tendency. Total feed and pasture intakes respectively decreased by 0.44 and 0.78 kg per day for each one kilogram increase in supplementation. The amount of concentrate consumed in addition to hay/grazing on pasture per unit weigh gain of the 4H group was slightly superior to that of the 2H and 8H groups. 【Conclusion】Thereby, the restriction of 4 h at pasture is sufficient for optimizing growth performance. With a combination of grasslands protection and feeding cost, it can be concluded that lambs offered 4 h access to pasture combined with 0.52 kg supplements of concentrate and grass hay (at a ratio of 1﹕1) is an optimum grazing management method.

Research on the Inhibitory Mechanism of Imazethapyr to Nodule Nitrogenase Activity in Soybean

LI Hui, DING Wei, JIANG Jun-Feng, WANG Huai-Biao

Scientia Agricultura Sinica. 2013, 46(19): 4173-4178. doi:10.3864/j.issn.0578-1752.2013.19.023

Abstract ( 487 )

PDF (528KB) ( 615 )

Save

References | Related Articles | Metrics

【Objective】The objective of this study is to discover the key inhibitory mechanism of imazethapyr to nodule nitrogenase activity in soybean for providing methods to resolve the toxity on nodule nitrogen fixation after imazethapyr being over used.【Method】A field experiment was conducted to determine the relationship between inhibited nodule nitrogenase activity and leghemoglobin content, ammonia content in nodule rhizobium and in nodule cytoplasm after imazethapyr pre-emergence used.【Result】Nodule nitrogenase activity was inhibited more pronounced during 21 days after treatment (DAT). One the 7 and 14 DAT, the inhibited ratio of leghemoglobin content peaked 30.52% and 35.41%, respectively at 112.5 and 25.0 g a.i./hm2 imazethapyr and then recovered to the levels of non-treated plants on the 21 and 28 DAT, respectively. The inhibited ratio of ammonia content in nodule rhizobium peaked 35.33% and 48.96%, respectively, on the 14 DAT and recovered to the levels of non-treated plants on the 28 DAT. Ammonia content in nodule cytoplasm increased more pronounced and recovered to the normal levels respectively on the 21 and 28 DAT.【Conclusion】It is an important reason that leghemoglobin content significantly decreased after imazethapyr pre-emergence applied leads to nodule nitrogenase activity inhibited, and ammonia accumulation in nodule cytoplasm also causes feedback inhibition to nodule nitrogenase.

Table of Content