Stereoselective degradation of ethofumesate in turfgrass and soil   总被引：2，自引：0，他引：2  

Ping Wang 《Pesticide biochemistry and physiology》2005,82(3):197-204

The stereoselective degradation of ethofumesate in turfgrasses and several agricultural soils was investigated to provide details of the fate of this chiral herbicide. Racemic ethofumesate was either foliar applied to two species of turfgrass or fortified into four types of agricultural soils. (+)- and (−)-Enantiomers were extracted and analyzed by a validated chiral HPLC method which involved extraction of samples with organic solvent followed by separation on cellulose-Tris-(3,5-dimethylphenylcarbamate)-based chiral column and quantification by UV absorbance at 230 nm. Mean recoveries of each enantiomer fortified at 0.5, 5, and 10 μg g⁻¹ ranged from 82.3 ± 5.84 to 92.5 ± 2.87% in turfgrasses and from 86.0 ± 5.09 to 98.1 ± 2.51% in soil. As a measure of this composition, the enantiomeric ratio (ER) was used, defined as the concentration ratio of (+)/(−)-enantiomer. Similarly, preferential degradation of the (−)-enantiomer was observed in both grass species with the largest ER of about 3 and in one of the test soil with ER = 1.65, resulting in residues enriched with (+)-enantiomer. This stereoselective degradation in this soil led to significant difference on half-lives between the two enantiomers. No stereoselective degradation was observed in other soils.  相似文献   

平阴玫瑰花粉亚显微形态及品种分类研究   总被引：18，自引：0，他引：18  

王文莉  赵兰勇  丰震  朱西存  张友朋  王延龄 《园艺学报》2005,32(3):527-530

 对平阴玫瑰24个品种的花粉亚显微形态进行了扫描电镜观察研究, 并进行了主成分分析和聚类分析。结果表明, 在花粉亚显微形态特征方面, 各品种之间既有共性, 也存在明显差别, 特别是外壁纹饰的不同可作为玫瑰品种鉴别的重要依据。聚类分析将平阴玫瑰花粉分为两大类, 即玫瑰系和蔷薇系, 与传统形态分类结论基本一致, 但也存在一定的差异。  相似文献   

瓜类嫁接栽培技术探讨   总被引：1，自引：0，他引：1  

刘大海  肖伟  罗章勇  陈义康  田时炳  王永清 《西南园艺》2005,33(1):7-9

从6个瓜类砧木品种中，选出了黄瓜适宜砧木为黑籽南瓜，苦瓜适宜砧木为黑籽南瓜和本地肉丝瓜，西瓜适宜砧木为超丰F1和欣京砧一号。瓜类嫁接方法以顶插接法和劈接法为宜，嫁接时期在3月初为宜。重病地黄瓜嫁接苗比自根苗枯萎病发病率降低95．8％，产量提高34．9％；嫁接苦瓜发病率降低83．7％，增产16．9％；嫁接西瓜发病率降低88．9％，增产13．7％。  相似文献   

Spatio-temporal modelling of broad scale heterogeneity in soil moisture content: a basis for an ecologically meaningful classification of soil landscapes     

Gimona  Alessandro  Birnie  Richard V. 《Landscape Ecology》2002,17(1):27-41

We describe the classification of landscapes characterised bymineral soil using a model that calculates soil moisture availability on amonthly basis. Scotland is used as a case study area. The model uses potentialsoil moisture deficit, estimated using broad scale (40 × 40 km)climate patterns, in conjunction with meteorological station measurements toobtain finer scale values of climatic soil moisture deficit. Point estimates ofsoil available water are obtained for soil characteristics using appropriatepedotransfer functions, and geostatistical techniques are used to upscale theresults and interpolate to a 1-km grid. Known heterogeneityin soil physical characteristics is used to provide local corrections to thepotential soil moisture deficit, estimated using the climatic variables above.Temporal profiles of monthly water content are modelled for each1-km location and classified into six classes usingunsupervised cluster analysis. The spatial distribution of these classesreflects regional variations in the availability of moisture and energy, onwhich finer-grained topographic patterns are superimposed. In the case study,the broad scale spatial heterogeneity of heathlands and grasslands on mineralsoils in Scotland is shown to be strongly related to the soil moistureclassification. The results can be used in studies investigating the patternsofdistribution of communities at the landscape and regional scale.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献   

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   

根结线虫的研究现状   总被引：50，自引：0，他引：50  

赵鸿  彭德良  朱建兰 《植物保护》2003,29(6):6-9

概述了根结线虫的发生分布和传统分类鉴定,以及分子生物学技术(同工酶电泳技术、DNA重组技术、PCR技术)在根结线虫种和生理小种鉴定中的运用及其防治,并对生物防治及抗根结线虫育种、转基因工程在植物线虫学研究领域上的应用前景作了展望。  相似文献   

小麦苗枯病菌的ITS分析及PCR检测   总被引：8，自引：0，他引：8  

葛芸英  郭坚华 《植物病理学报》2003,33(3):198-202

 小麦苗枯病菌(Clavibacter fangii,Cf)是引起小麦细菌性苗枯病的病原,本研究用16S~23S rDNA间的内源转录间隔区(internally transcribed spacer,ITS)序列通用引物L1(5'-AGTCGTAACAAGGTAGCCGT-3')和L2(5'-GTGCCAAGGCATCCACC-3')扩增Cf和其它相关细菌的基因组DNA;并对其PCR产物进行回收、克隆和测序,将所获序列和其它已报道的细菌ITS序列进行多重比较后设计出Cf的特异性引物I1(5'-TGCCAAGTCACACTGAGACGA-3')和I2(5'-CAATGATCTACCACCCTCCGA-3')。此引物可以从Cf中扩增出351bp的特异性片段,而其余参试的21个细菌PCR反应结果均为阴性。该方法可以应用于小麦苗枯病菌的快速、可靠检测。此外,本研究对多种植物病原棒形杆菌的ITS序列进行比较研究,发现其具有一定的分类意义。  相似文献   

盐池半荒漠风沙区土地沙漠化发生发展规律的研究   总被引：1，自引：0，他引：1  

孙德祥  王北 《干旱区资源与环境》1997,11(3):47-52

本文耐盐池半荒漠风沙区土地沙漠化发生发展规律进行了探讨，主要分析了在土地沙漠化的过程中土壤和植被的变化过程及其成因。  相似文献   

日光温室土壤盐分和养分的变化趋势   总被引：8，自引：0，他引：8  

吕福堂  司东霞  张秀省 《中国蔬菜》2004,1(3):14-16

对种植 1～ 8a的日光温室土壤盐分和养分进行了调查研究 ,结果表明 ,随着日光温室种植年限的延长 ,土壤可溶性盐、电导率、养分含量呈增加趋势 ,酸碱度 (pH)呈降低趋势 ,有机质含量增幅不大 ;土壤速效养分中硝态氮含量过高 ,速效磷含量也很丰富。最后提出了温室土壤培肥和管理措施。  相似文献   

不同覆土深度对鸡腿菇子实体产量的影响   总被引：7，自引：1，他引：7  

杨宣华  张维民  关仕港  麦焯棉  聂呈荣 《中国食用菌》2004,23(2):27-28

本试验研究 11种覆土深度对鸡腿菇子实体产量影响。结果表明 ,不同覆土深度对子实体产量、有效子实体数和幼蕾数均存在显著的影响。覆土越厚 ,幼蕾数越少。当覆土深度在 0 5～ 3cm时 ,子实体产量和有效子实体数随着覆土层的加厚逐渐增加 ,在覆土深度为 3cm时达到最大值 ,覆土深度大于 3cm时 ,则随着覆土层的加厚而逐渐减少。从生产的角度看 ,覆土 3cm是比较适宜的覆土深度 ,此时的子实体产量最高。  相似文献