吉林省荒地资源生态适宜性评价

本文从吉林省荒地资源的实际出发 ,在荒地资源生态适宜性评价基本理论的指导下 ,采用地理信息系统方法 ,对吉林省荒地资源进行了生态适宜性评价。通过空间数据和属性数据的融合、分析、处理 ,可以直观获得荒地资源的生态适宜度等级 ,从而提高评价效率 ,为荒地资源的合理开发利用提供科学依据。     

Engineering of a Single Chain Variable Fragment Antibody Specific for the Citrus tristeza virus and its Expression in Escherichia coli and Nicotiana tabacum

Citrus tristeza virus (CTV) is one of the most destructive citrus virus diseases in the world. The construction of an engineered antibody, EMBL accession number AJ278109, able to specifically recognize its antigen, i.e. the coat protein of CTV, directly on infected plant material without any purification or manipulation of the entire woody plant. The potential uses of this engineered antibody are discussed.     

Detection of Colletotrichum coccodes from soil and potato tubers by conventional and quantitative real-time PCR

Colletotrichum coccodes is the causal agent of the potato blemish disease black dot. Two PCR primer sets were designed to sequences of the ribosomal internal transcribed spacer (ITS1 and ITS2) regions for use in a nested PCR. The genus-specific outer primers (Cc1F1/Cc2R1) were designed to regions common to Colletotrichum spp., and the species-specific nested primers (Cc1NF1/Cc2NR1) were designed to sequences unique to C . coccodes . The primer sets amplified single products of 447 bp (Cc1F1/Cc2R1) and 349 bp (Cc1NF1/Cc2NR1) with DNA extracted from 33 European and North American isolates of C. coccodes. The specificity of primers Cc1NF1/Cc2NR1 was confirmed by the absence of amplified product with DNA of other species representing the six phylogenetic groups of the genus Colletotrichum and 46 other eukaryotic and prokaryotic plant pathogenic species. A rapid procedure for the direct extraction of DNA from soil and potato tubers was used to verify the PCR assay for detecting C. coccodes in environmental samples. The limit of sensitivity of PCR for the specific detection of C. coccodes when inoculum was added to soils was 3·0 spores per g, or the equivalent of 0·06 microsclerotia per g soil, the lowest level of inoculum tested. Colletotrichum coccodes was also detected by PCR in naturally infested soil and from both potato peel and peel extract from infected and apparently healthy tubers. Specific primers and a TaqMan fluorogenic probe were designed to perform quantitative real-time (TaqMan) PCR to obtain the same levels of sensitivity for detection of C. coccodes in soil and tubers during a first-round PCR as with conventional nested PCR and gel electrophoresis. This rapid and quantitative PCR diagnostic assay allows an accurate estimation of tuber and soil contamination by C. coccodes .     

Evaluation of resistance to Phytophthora cinnamomi in seed-grown trees and clonal lines of Eucalyptus marginata inoculated in lateral branches and roots

Seed-grown trees and six clonal lines of 3·5–4·5-year-old Eucalyptus marginata (jarrah) growing in a rehabilitated bauxite mine site in the jarrah forest were underbark-inoculated on lateral branches (1995) or simultaneously on lateral branches and lateral roots (1996) with isolates of Phytophthora cinnamomi in late autumn. Individual seedlings from which the clonal lines were derived had previously been assessed as either resistant (RR) or susceptible (SS) to P. cinnamomi . At harvest, the acropetal lesion and colonization lengths were measured. Overall, the length of colonization in roots and branches was more consistent as a measure of resistance than lesion length, because colonization length recorded the recovery of P. cinnamomi from macroscopically symptomless tissue ahead of the lesion which, on some occasions, was up to 6 cm. In both trials, one RR clonal line was able to contain the P. cinnamomi isolates consistently, as determined by small lesion and colonization lengths in branches and roots. In contrast, the remaining two RR clonal lines used in both trials were no different from the SS line in their ability to contain lesions or colonization. These latter two RR lines may therefore not be suitable for use in rehabilitation of P. cinnamomi -infested areas. Differences in lesion and colonization lengths among P. cinnamomi isolates occurred only in the 1995 trial. Colonization and lesion lengths in branches were up to eight times greater in 1996 than in 1995, but the relative rankings of clonal lines were consistent between trials. Although colonization was always greater in branches than roots, the relative rankings of the lines were similar between branch and root inoculations. Branch inoculations are a valid option for testing the resistance and susceptibility of young jarrah trees to P. cinnamomi .     

陕甘宁老区脆弱生态环境定量评价——以榆林、延安两市为例

位于黄土高原中部的陕甘宁老区生态环境极为脆弱 ,近年来由于气候、人类开发资源等自然和人为原因 ,使生态环境的脆弱程度升高。选定年降水量、年均温、蒸发量等 8个指标 ,定量评价各县 1 970 - 2 0 0 0年的脆弱度状况 ,结果表明榆林、延安两市生态环境整体脆弱 ,脆弱度存在空间差异但差异不明显 ,时间段上的波动幅度不大。陕甘宁老区脆弱生态环境具有不稳定性 ,对外界干扰较敏感。     

Bt对小地考虑呼吸作用的影响

利用红外CO2分析仪测定小地老虎幼虫呼吸节律的变化结果显示：小地老虎幼虫呼吸节律属于不规则波动型，取食含Bt烟叶的幼虫呼出的CO2量显著低于对照组，且呼吸节律的波动性也明显增大，说明小地考虑幼虫取食Bt后，呼吸代谢受到一定干扰，出现呼吸水平降低及代谢紊乱现象。     

梨自交不亲和强度不同品种花柱S糖蛋白含量的差异

 提取梨( Pyrus) 自交不亲和强度不同品种花柱可溶性蛋白质, 应用等电聚焦电泳法在凝胶板上分离出S 糖蛋白, 用图像解析法进行定量。结果表明, 花柱总S 糖蛋白含量因品种而异, 自交不亲和强、弱及自交亲和的品种每1 􀀁g 花柱可溶性蛋白中含总S 糖蛋白分别为􀀂1. 3 ng 、0. 7 ~ 0. 9 ng、 0. 7 ng 。不同的S 基因所表达的S 糖蛋白量差异显著, 即使是同一S 基因所对应的S 糖蛋白量也因品种而异。     

苹果梨中多酚氧化酶酶学特性的研究

 以苹果梨中的多酚氧化酶为研究对象, 对其酶的活性变化及其特性的研究表明, 苹果梨中的多酚氧化酶的最适pH 值是4. 6 , 最适温度是40 ℃; 亚硫酸氢钠、维生素C、柠檬酸对苹果梨中多酚氧化酶的抑制作用依次减弱, 硫酸钠几乎无抑制作用。不同底物和同底物不同浓度影响多酚氧化酶特性。     

核桃早实性状的RAPD分析

 用BSA (Bulked Segregant Analysis) 法获得了与核桃早实性状相关的RAPD 标记OPB208₉₀₀。混合分离群体的混合样来自早实品种辽1 的自然授粉实生后代。用220 个随机引物扩增早实和晚实混合样, 只有引物OPB208 ( 5. GTCCACACGG 3. ) 在早实混合样及其个体上扩增出了约900 bp 的特异带OPB208₉₀₀, 而在晚实混合样及其个体上无此特异带。用OPB208 为引物, 以19 个品种和3 个株系的DNA 为模板进行扩增,特异带OPB208₉₀₀在17 个早实品种中的12 个个体上出现, 而5 个晚实品种( 系) 上均无此带。