影响芋茎尖培养中脱毒和快速繁殖的几个生理因素

以3个芋品种（‘石川早生’、‘虾籽芋’、‘叶用芋）球茎茎尖为外植体,进行脱病毒和快繁的结果表明,外植体表面灭菌的最佳方法是剥鳞片→乙醇→新洁尔灭→剥幼叶→氯化汞;适宜茎尖分化的培养基为MS＋1．0-2．0mg·L^-16-BA＋0．2mg·L^-1 NAA。生物学方法和电镜观察显示：连续3代0．5-0．7mm茎尖剥离培养对芋花叶病毒（DMV）的脱毒率达100％。在培养基MS＋0．2mg·L^-1 NAA中,适量添加6-BA和TDZ,三品种芋的试管苗增殖效果好;附加KT,试管苗生长健壮且利于生根：添加20-100mg·L^-1的精胺（spm）,可促进不定芽的发生,与KT配合使用可促使继代增殖和成苗一步完成。完整植株在草炭土：蛭石=1：1的基质中,移栽成活率超过97％,且苗生长健壮。     

揭秘蚊子如何不受病毒感染影响

在对“黄热病”蚊子（埃及伊蚊）和蚊子传播的辛德毕斯病毒进行研究的一系列实验中,Kevin Myles及其同事发现了导致人类急性疾病的病毒如何无法显著影响其宿主蚊子的健康。     

The Role of Viral Infection in Inducing Variability in Virus-Free Progeny in Tomato

The effect of virus-host interactions on subsequent generations is poorly understood. The evaluation of the effects of viral infection on inheritance of quantitative traits in the progeny of infected plants and elucidation of a possible relationship between chiasma frequency in the infected plants and variability of traits in the progeny were investigated. The current study involved genotypes of four intraspecific hybrids of tomato （Solanum lycopersicum L.）, their parental forms and two additional cultivars. Used as infection were the tobacco mosaic virus （TMV） and potato virus X （PVX）. The consequences of the effect of viral infection were evaluated based on chromosome pairing in diakinesis and/or by examining quantitative and qualitative traits in the progeny of the infected tomato plants. Tomato plants infected with TMV ＋ PVX were found to differ in chiasma frequency per pollen mother cell or per bivalent. Deviations have been observed for genotypes of both F1 hybrids and cultivars. At the same time, differences in mean values of the traits under study have only been found for progeny populations （F2-F4） derived from virus-infected F1 hybrids, but not in the case of progeny of the infected cultivars. The rate of recombinants combining traits of both parents increased significantly （2.22-8.24 times） in progeny populations of hybrids infected with TMV＋PVX. The above suggests that the observed effects could be the result of modification of recombination frequencies that can be manifested in heterozygous hybrids and make small contributions to variability in cases of ＇homozygous＇ tomato genotypes （i.e. cultivars）.