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1.
With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty-two strains were further identified by Biolog, from which 133 were selected for fatty acid methyl ester (FAME) analysis together with 80 standard reference! strains. Six-teen species or types ofPseudomonas and 17 genera of non-pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed wereP. putida andP. fulva. About 17% of the strains ofPseudomonas and 2% of the non-pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents. Project supported by Belgium government and Asia Development Bank. Part of the experiments conducted at the University of Gent, Belgium and IRRI during 1997–2000.  相似文献   

2.
Seed vigor is an important characteristic of seed quality, and rice cultivars with strong seed vigor are desirable in direct-sowing rice production for optimum stand establishment. In the present study, the quantitative trait loci (QTLs) of three traits for rice seed vigor during the germination stage, including germination rate, final germination percentage, and germination index, were investigated using one recombinant inbred line (RIL) population derived from a cross between japonica Daguandao and indica IR28, and using the multiple interval mapping (MIM) approach. The results show that indica rice presented stronger seed vigor during the germination stage than japonica rice. A total of ten QTLs, and at least five novel alleles, were detected to control rice seed vigor, and the amount of variation (R 2) explained by an individual QTL ranged from 7.5% to 68.5%, with three major QTLs with R 2>20%. Most of the QTLs detected here are likely to coincide with QTLs for seed weight, seed size, or seed dormancy, suggesting that the rice seed vigor might be correlated with seed weight, seed size, and seed dormancy. At least five QTLs are novel alleles with no previous reports of seed vigor genes in rice, and those major or minor QTLs could be used to significantly improve the seed vigor by marker-assisted selection (MAS) in rice.  相似文献   

3.
Oil contaminated soil was collected from Huangpu River-Yangtze River estuary wetland, with the aim of isolating oil-degrading microorganisms and evaluating their ability to degrade diesel. Three bacterial strains were discovered and identified by sequencing their 16S rDNA genes, two were Pseudomonas and one was Alcaligcnes. The proper growth conditions of each bacterium were measured and presented for diesel biodegradation. Biodegradation assays revealed that the degradation rates of three bacterial strains were 42.5%, 14.6% and 15.9% in 7 d respectively. They all play an important role on the nalkanes within the range of C16-C25 components of diesel. The results indicated that the oil-degraders can adapt to degrade diesel. The bacterial strains can be used in wetland diesel pollution control.  相似文献   

4.
Pre-harvest desiccation may increase the efficiency of seed production. Field studies were conducted to determine the effects of diquat, paraquat, and ethephon applications on grain moisture, grain weight, and seed germination of hybrid rice Yanliangyou 88 (Oryza sativa ssp. indica) and conventional rice Wuyunjing 7 (Oryza sativa ssp. japonica). In 2013, we tested 12 treatments applied at four weeks (Yanliangyou 88) and six weeks (Wuyunjing 7) after heading. Results showed that reductions in moisture content were significant two and four days after chemical application. Chemical applications had no adverse effects on 1000-grain weight, germination percentage, or germination index, but there were negative effects on the percentage of normal seedlings. Desiccation effects increased with increase in the period after application, while the effect of ethephon combined with diquat or paraquat on desiccation was limited compared with that of diquat or paraquat alone in a short period after application. In 2013, chemical applications reduced the moisture content by from 0.5% to 6.4%, the germination percentage by from 0% to 3.3%, and the percentage of normal seedlings by from 13.3% to 100.0%. Among the treatments, diquat applied at 120 g/ha resulted in effective desiccation with fewer negative effects on grain weight and seed germination in 2013 and 2014. Therefore, diquat may have potential as a pre-harvest chemical desiccation treatment for rice. These results may provide a basis for developing and implementing protocols for large scale field trials.  相似文献   

5.
辣椒青枯病拮抗细菌的筛选及其鉴定   总被引：8，自引：0，他引：8  
从河南扶沟、江苏南京和淮阴等地的辣椒、番茄和黄瓜植物根围土壤中分离到100个细菌菌株.采用抑菌圈-定殖力双重测定法,筛选出5株终定植密度大于104cfu/g根、抑菌能力较强的细菌菌株;并对5个生物防治菌进行了生理生化测定.结果表明,5个生物防治菌分别属芽孢杆菌属、沙雷氏菌属、假单孢菌属和肠杆菌属.  相似文献   

6.
INTRODUCTIONAfterthewholericegenomewassequencedsuccessfully,moreandmoregenescanbepredictedwithdifferentsoftwaresandannotationsystem.However,thefunctionsofpredictedgeneshavetobefurtheridentifiedbybiologicalanalysis.Oneofthemostpowerfulmethodsassigningfunctiontogeneisthroughinsertionmutagenesiswithtrans-posableelementasDNAsequencetag.Ac/Dstrans-posonsystemhasbecomeaverypopulartoolforgenetaggingandfunctionalgenomicsinvariousplantspecies(Altmannetal.,1995;Chinetal.,1999;Enokietal.,1999;Gre…  相似文献   

7.
Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-element Ac/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision of Ds element was examined by PCR amplification. The excision frequency of Ds element varied from 0% to 40% among 20 F2 populations derived from 11 different Ds parents. Southern blot analysis revealed that more than 70% of excised Ds elements reinserted into rice genome and above 70% of the reinserted Ds elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The GUS positive lines will be useful for identifying gene function in rice.  相似文献   

8.
A machine vision system was developed to inspect the quality of rice seeds. Five varieties of Jinyou402, Shanyou10, Zhongyou207, Jiayou and IIyou were evaluated. The images of both sides of rice seed with black background and white background were acquired with the image processing system for identifying external features of rice seeds. Five image sets consisting of 600 original images each were obtained. Then a digital image processing algorithm based on Hough transform was developed to inspect the rice seeds with incompletely closed glumes. The algorithm was implemented with all image sets using a Matlab 6.5 procedure. The results showed that the algorithm achieved an average accuracy of 96% for normal seeds, 92% for seeds with fine fissure and 87% for seeds with incompletely closed glumes. The algorithm was proved to be applicable to different seed varieties and insensitive to the color of the background.  相似文献   

9.
Machine vision inspection of rice seed based on Hough transform   总被引：1，自引：0，他引：1  
INTRODUCTION It is a common phenomenon that glumes ofrice seeds are incompletely closed, especially forhybrid rice. The average proportion of hybrid riceseed with incompletely closed glumes is about 26%in nature. The threshing and drying in post-harvesthandling will further increase the proportion. Thegermen segmentation is inhibited by ultravioletillumination from sunshine while the germen epi-dermis cell stops growing because of shortage ofwater due to the limited moisture. These …  相似文献   

10.
Identification of rice seed varieties using neural network   总被引：1，自引：0，他引：1  
A digital image analysis algorithm based color and morphological features was developed to identify the six varieties (ey7954, syz3, xs1 1, xy5968, xy9308, z903) rice seeds which are widely planted in Zhejiang Province. Seven color and fourteen morphological features were used for discriminant analysis. Two hundred and forty kernels used as the training data set and sixty kernels as the test data set in the neural network used to identify rice seed varieties. When the model was tested on the test data set,the identification accuracies were 90.00％, 88.00％, 95.00％, 82.00％, 74.00％, 80.00％ for ey7954, syz3, xsl 1, xy5968, xy9308,z903 respectively.  相似文献   

11.
原油降解菌的筛选及其降解性能研究   总被引：1，自引：0，他引：1  
从茂名炼油厂附近长期被石油污染的土壤中分离出2株能够以原油为惟一碳源和能源的原油降解菌株,经鉴定分属假单胞菌属和芽孢杆菌属。进一步研究了2株菌原油降解特性及其影响因素,结果表明：2株菌5d原油平均降解率分别为42．8％和44．7％;在pH接近7．0,NaCI的质量浓度为10g/L,表面活性剂吐温-80的质量浓度为40mg／L时降解效果最佳。  相似文献   

12.
We characterized yield-relevant characters and their variations over genotypes and environments (locations and years) by examining two rice varieties (9746 and Jinfeng) with high yield potential.9746 and Jinfeng were planted in two locations of Shanghai,China,during 2005 and 2006.The results show that there was a large variation in grain yield between locations and years.The realization of high yield potential for the two types of rice was closely related to the improved sink size,such as more panicles per square meter or grains per panicle.Stem and leaf biomasses were mainly accumulated from tillering stage to heading stage,and showed slow decline during grain filling.Meanwhile,some photosynthetic characters including net photosynthesis rate (Pn),leaf area index (LAI),specific leaf area (SLA),fluorescence parameter (maximum quantum yield of PSII,Fv/Fm),chlorophyll content (expressed as SPAD value),as well as nutrient (N,P,K) uptake were also measured to determine their variations over genotypes and environments and their relationships with grain yield.Although there were significant differences between years or locations for most measurements,SLA at tillering and heading stages,Fv/Fm and LAI at heading stage,stem biomass at heading and maturity stages,and leaf nitrogen concentration at tillering and heading stages remained little changed,indicating their pos-sible applications as selectable characters in breeding programs.It was also found that stem nitrogen accumulation at tillering stage is one of the most important and stable traits for high yield formation.  相似文献   

13.
Genome segments S8 of two Chinese isolates of rice black-streaked dwarf virus (RBSDV), one from Zhejiang Province and another from Hebei Province, were amplified by RT-PCR and sequenced. Both segments consisted of 1936 nts in full length (EMBL accession numbers were AJ297431 and AJ297432, respectively) and contained only one big open reading frame which encoded a polypeptide with molecular weight of 68kD. The two Chinese isolates shared 94.0% and 96.5% identity at nucleotide and amino acid level, respectively. They shared 94.5-94.9% and 92.5-92.9% homology with S8 of RBSDV Japanese isolate at nucleotide and amino acid level, respectively; shared 85.1-87.6% and 91.7-91.9% homology with S7 of Italian MRDV (maize rough dwarf virus).  相似文献   

14.
Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-elementAc/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision ofDs element was examined by PCR amplification. The excision frequency ofDs element varied from 0% to 40% among 20 F2 populations derived from 11 differentDs parents. Southern blot analysis revealed that more than 70% of excisedDs elements reinserted into rice genome and above 70% of the reinsertedDs elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The GUS positive lines will be useful for identifying gene function in rice. Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2002AA2Z1003)  相似文献   

15.
从受石油产品污染土壤中筛选出5株石油降解菌,并通过生理生化实验对其进行了初步鉴定。石油降解能力的测定结果表明,其中KF-2、KF-4两株菌均为微球菌属Microrococcussp．）,石油降解能力较强,其单菌落接种20天后石油降解率分别可以达到76．21％、74．82％。在对这两株菌的降解特征的进一步探究中发现：KF-2菌株在NH4NO3作为氮源的条件下石油降解率较高;而KF—4在（NH4）2SO4作为氮源的条件下石油降解率较高。环境pH为7时,KF-2、KF-4的石油降解率都最高。混合菌的试验表明,KF-2、KF-4混合菌的降解效果明显好于各单菌株接种降解效果。  相似文献   

16.
The ecosystem characteristics of soil microorganism and the nutrient uptake of irrigated rice were investigated in a split-block experiment with different fertilization treatments, including control (no fertilizer application), PK, NK, NP, NPK fertilization, in the main block, and conventional rice and hybrid rice comparison, in the sub block. Average data of five treatments in five years indicated that the indigenous N supply (INS) capacity  相似文献   

17.
目的研究临床呼吸道感染病原菌的分布和耐药性。方法对2005年1月-2006年12月襄樊市中心医院门诊和住院部送检的呼吸道感染痰标本进行细菌培养和鉴定,分离出病原菌536株,并按照NCCLS标准用K-B法对临床肺部感染患者分离的病原菌进行药物敏感试验。结果共从1327份合格痰液标本中检出536株病原菌,以革兰阴性杆菌居首位,占66.04%,对亚胺培南的耐药性最低;革兰阳性菌占33.96%,对万古霉素100%敏感。结论:引起呼吸道感染的病原菌以革兰阴性菌为主,且耐药菌株逐年增加,铜绿假单胞菌和金黄色葡萄球菌是引起呼吸道感染的主要细菌,且其耐药性严重,合理使用抗生素对有效控制呼吸道感染和避免越来越多的耐药菌株出现尤为关键。临床上有呼吸道感染证候的可疑患者,应做痰液标本的细菌培养和药物敏感性试验,以避免在临床上盲目用药。  相似文献   

18.
公元前三世纪左右,日本进入弥生文化时期。弥生文化是比绳纹文化更为进步的一种新文化,水稻的栽培和铁器的开始应用是其主要特点。许多中日两国学者怀着对弥生文化自然演进的怀疑和通过对考古发掘遗物、遗迹的研究,认为日本的弥生文化是中国移民携带的大陆新文化要素促使形成的。在这一作用过程中,中国移民做出了不可磨灭的贡献。公元前二、三世纪,大批的中国人进入日本列岛。与此同时,他们向日本传入了从中国大陆带来的稻种、铁器、青铜器和水稻栽培技术及金属器具冶炼技术等,使日本由绳纹文化进入到弥生文化,对日本的社会发展产生了重大影响。  相似文献   

19.
Mutation breeding is based on the induction of genetic variations; hence knowledge of the frequency and type of induced mutations is of paramount importance for the design and implementation of a mutation breeding program. Although γ ray irradiation has been widely used since the 1960s in the breeding of about 200 economically important plant species, molecular elucidation of its genetic effects has so far been achieved largely by analysis of target genes or genomic regions. In the present study, the whole genomes of six γ-irradiated M2 rice plants were sequenced; a total of 144–188 million high-quality (Q>20) reads were generated for each M2 plant, resulting in genome coverage of >45 times for each plant. Single base substitution (SBS) and short insertion/deletion (Indel) mutations were detected at the average frequency of 7.5×10?6–9.8×10?6 in the six M2 rice plants (SBS being about 4 times more frequent than Indels). Structural and copy number variations, though less frequent than SBS and Indel, were also identified and validated. The mutations were scattered in all genomic regions across 12 rice chromosomes without apparent hotspots. The present study is the first genome-wide single-nucleotide resolution study on the feature and frequency of γ irradiation-induced mutations in a seed propagated crop; the findings are of practical importance for mutation breeding of rice and other crop species.  相似文献   

20.
微生物絮凝剂产生菌的筛选与生理生化鉴定   总被引：1，自引：0，他引：1  
采用稀释分离法和划线分离法从活性污泥中获得30多株纯化菌株,筛选获得2株高效絮凝菌株,利用发酵培养液对其进行絮凝实验并进行菌种鉴定。两株菌的絮凝率均在85％左右,两株菌的初步鉴定为芽孢杆菌属（N5）和变绿链霉菌（G15）。  相似文献   

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