Complexity of indica-japonica varietal differentiation in Bangladesh rice landraces revealed by microsatellite markers

To understand the genetic diversity and indica-japonica differentiation in Bangladesh rice varieties, a total of 151 accessions of rice varieties mostly Bangladesh traditional varieties including Aus, Boro, broadcast Aman, transplant Aman and Rayada varietal groups were genotyped using 47 rice nuclear SSRs. As a result, three distinct groups were detected by cluster analysis, corresponding to indica, Aus and japonica rice. Among deepwater rice varieties analyzed some having particular morphological features that mainly corresponded to the japonica varietal group. Some small seeded and aromatic varieties from Bangladesh also corresponded to the japonica varietal group. This research for the first time establishes that the japonica varietal group is a prominent component of traditional varieties in Bangladesh, particularly in deepwater areas.     

不同施肥模式和投入水平对甘蔗产量影响及效益分析

随着近年来肥料和劳力价格的不断上升,为了降低糖料蔗的生产成本,提高种蔗经济效益,本文进行按每亩投入施肥量为250元、300元、350元、400元四种不同水平以两次和多次施肥方法的田间试验,本试验结果表明,以每亩投入350元肥料款,下足基肥和一次追肥的施肥方法获得10513kg/667m2较高的产量和最好的经济效益,肥料用款400元/亩的高投入和4次施肥方法,虽然可获得11173kg/667m2的最高产量,但施肥花费劳动力成本增加较大,沒有获得最好的经济效益。     

Influence of soil factors on the soil enzyme inhibition by Cd

A comparative study was conducted on the toxicity of Cd to alkaline phosphatase activity (ALP) and dehydrogenase activity (DHA) in 18 top soils with contrasting soil properties representative of 14 major soil types in China. Soil pH and carbonate content, soil organic matter, and cation exchange capacity (CEC) largely affected the Cd toxicity on two enzyme activities; with the soil pH having only minor effect on the median ecological dose values based on total Cd concentrations (ED_{50 T}). The values of ED_{50 T}/ED_{50 W} (based on water-soluble Cd content) of alkaline phosphatase and dehydrogenase were strongly influenced by pH and CEC contents, which explained up to 71% of the variation for alkaline phosphatase, 82% of the variation for dehydrogenase, and also were significantly correlated with the parameter K_F derived from Freundlich adsorption isotherms. This study suggests that the values of ED_{50 T}/ED_{50 W} could be useful to evaluate the buffer capacity of soils which protects soil enzymes from harmful effects of heavy metal.     

海岸带风口沙地提高木麻黄造林效果的研究

自１９９８年５月以来，在福建省惠安县赤湖林场和东山县赤山林场木麻黄基干林带前沿风口干旱沙地，进行提高木麻黄造要效果配套技术研究。经２年试验研究，在分析风口困难立地造林失败主要原因基础上，从木麻黄抗逆品系选择应用，因地制宜确定造林方式，采用深挖整地、放客土、拌泥浆、提早造林季节、选择大雨天冒雨造林、大苗深栽等抗旱造林配套技术以及旱季培土抚育保墒、浇水保苗和筑沙堤设风障防潮防风工程措施相结合的造林方法     

籼型三系不育系丰源A的选育

丰源Ａ由湖南杂交水稻研究中心与广西钟山县种子公司合作育成，于１９９８年通过湖南省科委鉴定，是一个育性稳定、配合力强、异交结实率高、米质较优、抗逆性较强的籼型三系不育系     

湖南省普通高校生均成本的探讨Ⅰ.生均成本现状的调查与分析

为了解湖南省高等教育经费投入与高校生均支出成本之间的关系,对1985,1993,1994和1995年4个年度湖南省属8所高等学校的生均支出成本和办学条件等基本情况进行了调查和分析.结果表明,在1985～1994年年间,湖南省高等学校得到了较快发展,规模效益也有了明显提高.但是,由于政府对高等教育的投入不能满足办学的需要,加之本科办学规模扩大过快,导致了本科院校办学条件的逐年下降.     

棉蚜对溴氰菊酯不敏感性与水解酶的变化初探

本文采用生物测定和生物化学方法就棉蚜(Aphis gossypii Glover)在不同地区不同时期对溴氰菊酯不敏感性与水解酶的变化进行了初步研究。结果表明:新乡地区棉蚜对溴氰菊酯存在高倍不敏感性。同一地区,蕾铃期棉蚜不敏感性高于苗期棉蚜。在离体条件下,棉蚜羧酸酯酶的活力随着棉蚜对溴氰菊酯不敏感性增加而增加。磷酸酯酶活性变化则不显著。     

小麦梭条斑花叶病毒(WSSMV)提纯、粒子性质和血清学

 采用冰冻患病小麦叶片,经0.5M磷酸钾缓冲液pH7.0抽提,1/4体积四氯化碳澄清,6%聚乙二醇,3% NaCl和1% Triton X-100沉淀,二次差速离心(含20%蔗糖垫,0.3% Triton X-100).一次10-50%蔗糖密度梯度离心,最后经一次超速离心浓缩,成功地获得部分提纯制剂。经电镜观察,可见大量线状病毒粒子,很少有杂质。病毒粒子在中性条件下稳定,在酸性条件下变形。病毒粒子直径13-14nm.长度250-1800nm,其中在300-400nm,550-700nm之间具有二个主要分布峰。经紫外读数,病毒制剂表现为典型的核蛋白吸收特性.其中OD260/OD244为1.19,OD260/OD280为1.29。病毒粒子外壳蛋白有二个组分,分子量分别约为30kd和27kd。
在免疫电镜实验中,小麦梭条斑花叶病毒(WSSMV)和小麦黄花叶病毒(WYMV)抗血清不仅均能显著而有效地捕获汁液中的WSSMV粒子,而且还可在粒子外面包上一层厚厚的抗血清外套。     

甘肃省干旱半干旱地区降水的研究

本文通过对甘肃省降水资料的具体分析,指出了在干旱、半干旱地区降水的主要特征,如暴雨的特殊性、固体降水与海拔关系、降水量与海拔关系、降水量与作物产量关系等,并对如何提高降水利用率,发展农业生产等问题进行了探讨。