Inconspicuous restraint of rice seedling growth by root-infecting fungi in soil of a rice paddy field     

Hiromitsu Furuya  Tsutomu Matsumoto  Shin-ichi Fuji  Hideki Naito 《Journal of General Plant Pathology》2003,69(2):115-119

 Rice seedling growth, estimated by plant height and root development and discoloration, was better in pasteurized soil than in unpasteurized soil obtained from a flooded rice field. Rice seedlings also grew better in sterilized soil modified by adding roots harvested from the pasteurized soil than in soil modified by adding roots harvested from the unpasteurized soil. The results demonstrate that seedling growth in the rice field soil was inhibited by soil microorganisms, even though no typical symptoms such as seedling blight or damping-off appeared. Pythium aristosporum is suggested to be involved in the inhibition. Thus, it appears that inconspicuous restraint of rice seedling growth could occur in soils of rice paddy fields. Received: May 20, 2002 / Accepted: October 16, 2002 Acknowledgments The authors thank Dr. T. Ichitani, former professor at Osaka Prefectural University, for providing an isolate of Pythium aristosporum for comparison, and Mr. Mitsuaki Sato of Akita Prefectural College of Agriculture for technical assistance.  相似文献   

棉蚜预测预报网络数据库系统的设计与开发   总被引：2，自引：1，他引：2       下载免费PDF全文

吕昭智  沈佐锐  田长彦 《植物保护学报》2003,30(3):237-242

依据棉蚜Aphis gossypii Glover测报的国家行业标准(GB／T15799．1995)及其测报调查的相关信息标准，利用分布式数据库SQL建立了棉蚜预测预报数据库，数据库主要包括早春木本寄主蚜虫调查、早春草本寄主蚜虫调查、苗期棉蚜消长情况调查、苗期棉蚜普查、伏期棉蚜系统调查、伏期棉蚜普查、棉田天敌系统调查、植保站信息和气象信息等12个数据表；利用Internet网络技术和网络开发软件，建立了浏览器／服务器应用程序结构体系，实现了棉蚜虫情数据维护、查询、统计、报表和打印等网络数据库管理和预测数据挖掘功能。棉蚜网络数据库的建立和浏览器／服务器应用程序结构体系的组建和实现，为棉蚜区域化预测预报和管理提供了有力的科学和技术支持。  相似文献   

黄瓜幼叶细胞中钙调素的免疫胶体金定位     

田景花  张红  李明  王梅 《园艺学报》2003,30(6):728-730

 采用免疫胶体金电镜技术对黄瓜幼叶叶肉细胞中的钙调素(CaM)进行定位。结果表明：适温下生长的黄瓜幼苗叶肉细胞中的CaM主要分布于细胞核和叶绿体内，细胞核中CaM主要存在于染色质和核仁上，叶绿体中CaM主要存在于类囊体膜上；线粒体中也有一定量的CaM分布；细胞质、液泡、液泡膜及质膜上只有少量CaM存在；而细胞壁和细胞间隙却很难发现显示CaM存在的金颗粒。  相似文献   

类开菲尔粒发酵特性的研究     

王和平  田瑞华  乌云  黄艳萍  杜美丽  刘歆瑜 《乳业科学与技术》2004,26(4):153-155

该研究揭示了类开菲尔粒发酵乳酸度受发酵条件影响的主次顺序分别为时间、温度、接种量；乙酸、乳酸含量受发酵条件影响的主次顺序分别为温度、时间、接种量；甲酸含量受发酵条件影响的主次顺序分别为温度、接种量、时间。1：10接种、37℃条件下发酵16小时产酸量较高.  相似文献   

长寿花胚性愈伤组织的诱导及胚状体再生   总被引：10，自引：0，他引：10  

陈超  王桂兰  田立民  崔瑞生 《园艺学报》2004,31(2):249-252

 研究了长寿花胚性愈伤组织的筛选，胚状体的诱导发生、发育过程及植株再生。经过对外观及细胞学观察，看出外观质地疏松、颗粒状的淡黄色愈伤组织细胞圆形且形状规则，是胚性愈伤组织。诱导胚性愈伤组织的最适培养基为：MS+2，4-D 2 mg·L^-1 +BA 0.2 mg·L^-1；胚状体的诱导培养基为MS+BA 2 mg·L^-1 +NAA 0.2 mg·L^-1 +活性炭4 g·L^-1+蔗糖30 g·L^-1，胚状体诱导率可达185个胚状体；胚状体的再生培养基为MS+蔗糖30 g·L^-1。利用石蜡切片对胚状体的发生过程进行了观察。  相似文献   

Functional heterogeneity in resources within landscapes and herbivore population dynamics     

Norman Owen-Smith 《Landscape Ecology》2004,19(7):761-771

Large mammalian herbivores are notorious for their propensity towards population irruptions and crashes, yet many herbivore populations remain relatively stable. I explore how resource heterogeneity within landscapes dampens population instability, using a metaphysiological modelling approach considering patch state distributions. Resource heterogeneity is functionally stabilizing through spreading consumption away from preferred resources before these become critically depleted. Lower-quality resources act as a buffer against starvation during critical periods of the seasonal cycle. Enriching resource quality is destabilizing, even if patch diversity is maintained, because food quantity then becomes the limitation. The potential consequences of landscape fragmentation are explored using the Serengeti ecosystem, characterised by broadscale resource gradients, as a hypothetical example. Further insights provided by the model are illustrated with specific examples concerning the effects of patch scales and waterpoint distribution. A metaphysiological modelling approach enables the basic consequences of landscape heterogeneity to be distinguished from further effects that may arise from specific patch scales and configurations, without the distracting detail of spatially explicit models.  相似文献   

30%毒死蜱微乳剂的研究、性状及药效   总被引：3，自引：0，他引：3  

田文学  王开运  闫新华 《农药科学与管理》2004,25(11):27-29

本文介绍了30％毒死蜱微乳剂配方的组成和制备方法．并对其性能和田间药效进．行了测试和试验。  相似文献   

Validation of the specificity and sensitivity of species-specific primers that provide a reliable molecular diagnostic for <Emphasis Type="Italic">Xiphinema diversicaudatum</Emphasis>, <Emphasis Type="Italic">X. index</Emphasis> and <Emphasis Type="Italic">X. vuittenezi</Emphasis>     

Judith Hübschen  Lilo Kling  Ulrike Ipach  Volker Zinkernagel  Nathalie Bosselut  Daniel Esmenjaud  Derek J.F. Brown  Roy Neilson 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):779-788

Xiphinema diversicaudatum and X. index are vector nematode species of economic importance in viticulture regions as they can transmit Arabis Mosaic, Grapevine Fanleaf and Strawberry Latent Ringspot viruses to grapevine. Wang et al. (2003) designed species-specific diagnostic primers from ribosomal genes for both these vector species as well as a vector and a non-vector species X. italiae and X. vuittenezi, respectively. Our study aimed to confirm the specificity and determine the sensitivity and reliability of the primers for the two vector species, X. diversicaudatumand X. indexwhen challenged with closely related longidorid species and general nematode communities typical of vineyard soil. With one exception, no PCR product was observed when the primers were tested against six Longidorus, one Paralongidorus and one Xiphinema non-target species. Occasionally (three out of eight replicate PCR reactions) a weak PCR product was noted when primers for X. index were tested with L. elongatus. Furthermore, when challenged with a range of non-target nematode species comprising the nematode community typical of viticulture soil, no PCR product was amplified. An experimental dilution series of extracted DNA rigorously demonstrated that DNA from an equivalent single specimen of the target virus-vector species, X. diversicaudatum and/or X. index, could be detected amongst 1000 equivalent non-targetX. vuittenezi. Also, extracted DNA from an equivalent single target specimen was detected when added to DNA extracted from the overall soil nematode community. The primers were assessed further by using serial mixtures of actual nematodes rather than extracted DNA to simulate field soil. Using this method, a single target nematode could be detected amongst 200 non-target specimens. Given their specificity, sensitivity and reliability, it appears that these diagnostic primers will be of great benefit to phytosanitary/quarantine services related to the viticulture industry.  相似文献   

秦巴山区养羊户适度经营规模的研究   总被引：1，自引：0，他引：1  

罗军  姚峘  田冬华  王斌  刘强  赵新发  杨和英 《中国草食动物》2004,24(2):7-10

通过对秦巴山区陕西省西乡县15个典型陕南白山羊养殖专业户的资金投入、羊群结构、草地资源、经济效益等情况的调查，分析了养羊户的资源利用和生产经营状况，确定了与山羊生产密切相关的12个变量，即种公羊数、基础母羊数、后备母羊数、育肥羊数、羊舍面积、草地补种及施肥费用、医杂费、氨化或青贮饲料量、补饲精料量、工作日、投资额，并确定了各变量的参数值，以利润最大为目标函数，然后运用线性规划模型，计算出不同投资、不同人力及草地资源等条件下的适度经营规模。结果表明，养羊户的投资额是决定适度规模的主要因素。根据投资和羊群基础母羊数量设计的三种典型经营条件下，基础母羊全部留种的经营方式可获最大投资收益率(140．1％)；基础母羊数量达到20只以上，自繁种公羊的经营方式的最大投资收益率为74．0％；资金有限，人工授精配种的经营方式的投资收益率最低，为73．1％。  相似文献   

水产动物诱食剂的研究进展     

李红军  田夏清 《饲料研究》2005,(3):57-59

在水产养殖中 ,很多饲料投放后未被动物采食就沉入了水底 ,不但浪费了饲料 ,而且还污染了水质和提高了饲料成本 ,而水产动物诱食剂可以缓解这些问题。  相似文献