硒对生菜抗氧化酶活性及光合作用的影响

以盆栽试验研究了叶面喷施不同浓度硒对生菜SOD、POD、MDA、光合特性及生长的影响。结果表明：低浓度硒提高了SOD、POD活性,净光合速率、蒸腾速率和气孔导度,促进了生菜生长,而高浓度硒则起抑制作用;MDA随着喷施硒浓度的增大呈升高趋势,胞间CO2浓度随喷施硒浓度的增加而增加。总之,适量的硒处理能增强生菜的抗氧化能力和光合作用,提高产量。     

番茄果实总RNA提取与cDNA-AFLP

从番茄果实中提取高质量的RNA是对调控番茄果实品质、生长发育和代谢等相关基因进行分子生物学研究的基础。实验表明,已报道的相关RNA的提取方法,即使利用已经报道的从其它果实中成功提取出高质量RNA的方法,也不能从番茄果实中分离出高质量的RNA。 这主要是由于番茄果实中多糖、多酚类物质及其他次生代谢,在RNA提取过程中与RNA共同沉淀,从而影响RNA的产量和质量。目前,商业化的RNA抽提试剂盒无法直接用于番茄果实RNA的提取。笔者采用4种方法对番茄果实总RNA进行提取,筛选出一种最佳的改进方法。可以从不同时期番茄果实中成功提取高质量的RNA,产量可达401.6--840.2μg/g,通过测定A260/A230和A260/A280 的比值表明,该方法排除了番茄果实中蛋白、多糖、以及多酚等次生物质的干扰,提取到了高质量番茄果实总RNA;1.2%琼脂糖电泳结果表明RNA在整个提取过程中结构完整,未发生明显降解;所提取的RNA用于cDNA-AFLP等到了清晰的表达图谱,这表明其质量完全可满足下一步分子生物学研究。     

Deposition patterns in bulk precipitation and throughfall in a subtropical mixed forest in central-south China

The chemistry and deposition pattern in bulk precipitation andthroughfall (TF) were examined and evaluated based on the 3-yearobservations in Shaoshan subtropical deciduous-conifer mixedforest in central-south China. The TF chemistry was notablychanged when passing through canopies, which probably was attributedto the dry deposition (DD) on leaf surface and the canopy exchanges.Base cations' (Ca²⁺, Mg²⁺ and K⁺) fluxes were significantlyenriched in TF, in particular for K⁺. The annual K⁺ canopy exchangewas 12 times larger than DD, and canopy exchange of Ca²⁺, Mg²⁺and K⁺ was four times as high as the DD. The canopy exchangeof base cations in association with weak acid accounted for28.4 per cent of total leached base cations, which was one ofthe important factors to modify the TF chemistry.     

关中西部农业产业化的现状与对策

大力推进农业结构不断优化升级,实现产业化经营,是提高中国农业的整体素质、综合效益和国际竞争力的有效途径。在分析关中西部资源、产业现状、制约因素的同时,提出了促进关中西部农业产业化发展的对策和建议。     

论江苏稻米产业经济的地位和功能及其发展战略

从经济学角度提出了稻米产业经济的概念及其基本特征,论述了江苏稻米产业经济在江苏省国民经济中的基础性地位,认为江苏稻米产业是江苏农业经济发展的基础,是江苏农业可持续发展的保障,是保障江苏粮食安全的前提。是现代工业经济的重要组成部分,同时还提出了江苏稻米产业经济的区域、科技、工业、品牌、长效五大发展战略。     

Differences in cultivar response and complete sequence analysis of two isolates of wheat yellow mosaic bymovirus in China

Seeds of selected European and Japanese winter wheat cultivars were grown at two experimental sites in China, namely Yaan, Sichuan province (YA), and Yangzhou, Jiangsu province (YZ), where wheat yellow mosaic bymovirus (WYMV) was severe. There were some differential responses of the cultivars to the virus isolates present at the two sites. The complete nucleotide sequence of both RNAs of both virus isolates was determined. Their genome organization was identical to that reported for a Japanese isolate and the sizes were very similar. Nucleotide comparisons demonstrated that parts of the CI and NIa coding regions on RNA1 and the N-terminal part of the P2 coding region on RNA2 were particularly variable, while substantially conserved regions occurred in the 3' UTR of RNA2, the 7K, one part of the CI and parts of the NIb and coat protein. It seems unlikely that differences in the 7K and NIa-VPg proteins are responsible for virulence differences and the CI and NIb regions were considered the most promising for further study.     

有机农业和土壤生物多样性

（中国农业大学农学与生物技术学院有机农业技术研究中心,北京,100094）     

中国有机茶生产技术的研究和应用

系统的介绍了有机茶的概念、意义、发展过程及有机茶生产技术的研究概况。     

寡聚半乳糖醛酸防治苹果花叶病田间药效试验

应用寡聚半乳糖醛酸对苹果花叶病进行了田间药效试验,结果表明：寡聚半乳糖醛酸水剂稀释300~500倍,对苹果花叶病防效达87.81%~92.08%。其防效比对照药剂20%病毒的防效81.11%高, 比对照区增产20%~23%。是防治苹果花叶病较理想的药剂。     

木醋液及其主要成分对土壤微生物数量影响的研究

木醋液是从多年生柞木中经过高温蒸馏出来的纯天然物质,其主要成分是有机酸和酚类物质,为了明确木醋液和主要成分对土壤微生物的作用,将加入不同剂量的木醋液、愈创木酚、醋酸的有机肥施入土壤,观察土壤中微生物数量的变化,结果表明：在1kg有机肥中加入10g木醋液,施入30kg土壤中,土壤微生物数量（特别是细菌数量）增加幅度最大,土壤微生物10天内被有效地激活;同时,当在1kg有机肥中木醋液的添加量高达50g时,对土壤微生物有一定的抑制作用。此外,通过采用木醋液中的两种主要成份醋酸与愈创木酚对比试验,表明其对土壤微生物数量的影响与木醋液不相关,木醋液能起到增加土壤微生物数量的作用,虽然有可能是其他物质在起主导作用,但更有可能的是多种物质的综合作用。