冬青抑菌活性的初步研究

采用生长速率法,测定冬青(Ilex purpurea Hassk)不同器官的提取液对小麦纹枯病菌(Rhizoctonia cerealis)、番茄褐斑病菌(Helminthosporiurn carposaprum)、番茄早疫病菌(Alternaria solani)、黄瓜褐斑病菌(Corynespora cassiicolai)的抑菌作用.结果表明,当浓度为0.1 g/mL时,冬青不同器官的提取液对4种病原菌菌丝生长都有一定的抑制作用,但不同部位提取液的抑菌活性不同,其中冬青果实和枝条提取液的抑菌活性较弱,树皮提取液的抑菌活性次之,叶片提取液的抑菌活性较强.     

旋花科植物ITS序列分析

通过提取白色圆叶牵牛基因组的DNA及紫色重瓣圆叶牵牛的DNA,对其内转录间隔区(ITS)序列进行PCR扩增和序列测定.采用BLAST方法,将测序结果在GenBank中进行同源搜索,采用邻接距离矩阵法构建了与其亲缘关系接近的旋花科14个种基于ITS序列的系统发育树,并分析了它们的亲缘关系.结果表明,原牵牛属和番薯属的亲缘关系较近,打碗花属、旋花属与番薯属为旋花科两大亲缘关系较远的类群;疑似新种的紫色重瓣圆叶牵牛并非一个新种,而是属于圆叶牵牛种下分类水平的变种或变型.     

金边龙舌兰的开花与栽培繁殖研究(英文)

金边龙舌兰是多年生草本植物。记述了其分类分布、形态特征、生活习性、开花结果、栽培繁殖及日常用途等知识,为金边龙舌兰的开发利用提供了借鉴。     

Study on the Phenotypic Mutation Generated from ~(60)Coγ-ray Irradiated Oxlias triangularis Purpurea Regeneration System

Mutations induced from tissue culture are easily to be separated,which might be propagated in the same medium,especially for the color-leaf ornamental grass,Oxalis triaggularis purpurea.Mutations of the ornamental traits in the tissue culture bottle could be investigated easily.The 35 d regeneration system group showed the lowest adventitious bud number and adventitious root number among 4 inoculation dates by 50 Gy dose of ~(60)Coγ radiation.More studies were carried out based on the 35d differentiation state of O.triangularis purpurea regeneration system.The 35 d regeneration system was then irradiated by 10,25 and 50 Gy doses of ~(60)Coγ rays.Numbers of adventitious buds and roots induced from the regeneration system were cut down with the increment of radiation doses.Seedling length was not distinctly reduced at the absorbed doses of 10 and 25 Gy,but reduced distinctly under 50 Gy of ~(60)Coγ irradiation.The optimal irradiation dose for 35 d O.triangularis regeneration system survival and mutation induction was approximately 25 Gy.The M_2 phenotypic mutation rate was 2.9%,especially,and the leaf number mutation accounted for 76%of the total mutation.The phenotypic mutations,especially in the 10 Gy group,on 0.1 m M Vc containing MS medium were recovered,which indicated that ROS plays a key role in the phenotypic mutation induced by ~(60)Coγ -rays.     

Acaricidal effects of cardiac glycosides, azadirachtin and neem oil against the camel tick, Hyalomma dromedarii (Acari: Ixodidae)

The cardiac glycoside, digitoxin, from Digitalis purpurea L (Scrophulariaceae), a cardiac glycosidal (cardenolide) extract from Calotropis procera (Ait) R Br (Asclepiadaceae), azadirachtin and neem oil from Azadirachta indica A Juss (Meliaceae) were tested for their effects against larvae and adult stages of the camel tick, Hyalomma dromedarii Koch (Acari: Ixodidae). The contact LC50 values of the first three materials against adults were 4.08, 9.63 and >40.7 microg cm(-2), respectively, whereas the dipping LC50 values of the four materials were 409.9, 1096, >5000 and >5000 mg litre(-1), respectively. Contact and dipping LC50 values of the extract and azadirachtin against larvae were 6.16, >20.3 microg cm(-2) and 587.7 and >2500 mg litre(-1), respectively. Azadirachtin had no effects on egg production or feeding of adults up to 5000 mg litre(-1); however at 2500 mg litre(-1), it caused significant reduction in feeding activity of larve, prolonged the period for moulting to nymphal stage, and caused 60% reduction in moultability. Results of the two cardiac glycoside materials are comparable with those of several commercial acaricides. The risks and benefits associated with the use of cardiac glycosides are considered.     

红菜薹自交不亲和性快速测定初报

红菜薹的自交不亲和性表现为柱头抑制。授粉后24h的柱头,在电镜和荧光镜下观察,即可对其不亲和性进行测定。有些单株老龄花亲和性比幼龄花亲和性稍高。亲本亲和指数同后代条和指数的平均值呈正相关,因此在选择时,最好选择那些亲和指数低,不亲和性强的单株。     

沙田柚自交和异交亲和性观察

用荧光显微镜和扫描电镜对沙田柚（Ｃｉｔｒｕｓｇｒａｎｄｉｓｖａｒ．ｓｈａｔｉｎｙｕＨｏｒｔ．）自交和异交亲和性进行了观察。沙田柚自、异交授粉后，花粉管通过柱头乳突细胞间隙进入柱头，先是在柱头区沿细胞间隙生长，长到花柱区后，一直沿花柱道内缘通道细胞长入子房。当花粉管伸长到花柱１／４～１／２时，自异交的花粉管生长速度和管壁胼胝质积累出现差异，自交花粉管在花柱１／２左右处停止生长，异交花粉管正常进入胚囊受精。花柱切面自交授粉管能萌发，但不能进入花柱道。花柱切面异交授粉和胎座授粉，花粉管均能进入胚囊，进行受精。柱头分泌液和柱头匀浆提取液进行花粉离体萌发，花粉能正常萌发和生长。实验结果表明，沙田柚自交不亲和识别和阻抑部位在花柱，属配子体不亲和型。     

青海湖地区紫花针茅型中度与重度退化草地地下植物量的比较研究

对青海湖地区紫花针茅型中度与重度退化草原地下植物量进行了比较研究,结果表明,中度与重度退化样地地下植物量的季节积累动态并不相同,随着退化程度加重,在草地植物地上部枯黄之前,光合产物向地下部的运转减少,根部贮藏的营养物质减少,地下与地上植物量的比值随退化程度的加重而增大。两个退化样地地下植物量的80%分布在0~20 cm土层,用y=axb能够很好描述中度与重度样地在生长季各土层平均分布的植物量及其所占比例。在40 cm深的土层中,中度与重度退化样地地下植物量每年的净生产量分别为849.6 g/m21、346.05 g/m2;周转值分别为32.45%、51.93%。     

原始林内紫果云杉种群的 数量动态

本文将紫果云杉种群看作是由不同径级林木所组成的群体，借以Leslie矩阵描述其数量动态情况，由此得种群Leslie矩阵的特征根λ＝1．028，对应特征向量亦即种群稳定的级径组成为：（9941，783，556，393，280，116，32，8）。结果表明：在原始林内，紫果云杉种群结构较为稳定，呈增长稳定型；经预测，种群未来的结构组成与现在的相似。     

龙桑曲枝性遗传的再研究

龙桑是桑树的一个栽培品种,它的最大特点是具有曲枝性,本文对龙桑曲枝性遗传作了进一步的研究。研究结果表明,用龙桑嫁接苗天然授粉的种子培育的具有曲枝性状的龙桑实生苗,相互传粉所获得的种子再培育的实生苗,其中有75％的幼苗表现为曲枝性,25％的幼苗表现为直枝性。进一步证明了,龙桑曲枝性遗传机制符合一对显隐性基因的分离和自由组合规律。