不同处理对黑草种子发芽能力影响的研究

黑草野生资源逐渐减少,研究黑草种子的报道也较少。通过对贵州省望谟县野生黑草种子的研究,发现经过不同处理后,黑草种子发芽能力有很大差异,研究结果表明:低温浸种6 h的黑草种子最先露白,发芽率和发芽指数也较高,而且黑草种子适合生长于pH值为6.5的环境中,过酸或过碱会使其不发芽,同时,施加一定浓度的GA溶液会使黑草种子提前露白发芽,发芽率和发芽指数都会提高,但是浓度过高,又会使得黑草发霉。     

药用植物黑草种子萌发特性研究

采用正交试验设计,研究了贮藏温度、激素类别、激素浓度对药用植物黑草种子萌发特性的影响。结果表明,种子质量因子和发芽整齐度因子分别为第1、第2主成分,2个因子的方差累计贡献率在65%以上;贮藏温度、激素浓度对种子萌发的影响较大,激素类别次之;黑草种子萌发效果最佳组合为：-20℃低温贮藏并经100 mg/L 的6-BA 植物激素处理。     

Addressing current and future problems of parasitic weeds in rice

Significant areas of rain-fed rice in the Sahel, savannah and derived savannah zones of sub-Saharan Africa (SSA), Madagascar and other Indian Ocean Islands are infested by parasitic weeds. The affected area accommodates some of the poorest farmers of the world. Without appropriate management parasitic weeds in rice are expected to increase in importance in SSA due to their general invasive nature and their abilities to adapt to changing conditions such as imposed by predicted climate changes. The most important parasitic weeds in rice are: Striga hermonthica, Striga asiatica, Striga aspera and Rhamphicarpa fistulosa. The first two are primarily found in free-draining uplands while S. aspera is also found on hydromorphic soils and R. fistulosa is restricted to unimproved lowlands including inland valleys. As parasitic weeds are typical production constraints in subsistence rice production, targeting them would directly contribute to poverty alleviation and food security. This paper provides an overview of the problems caused by parasitic weeds in rice and discusses management options and opportunities for research for development.     

桃蚜与其内共生菌Buchnera之间的系统进化关系分析

为进一步明确桃蚜与其内共生菌Buchnera之间系统进化关系,参照前人研究蚜虫系统进化所用的COⅠ／COⅡ、12S／16SrRNA、EF-1 alpha的3对引物,对桃蚜的COⅠ／COⅡ、12S／16SrRNA、EF-1 alpha基因进行了扩增,并构建了桃蚜COⅠ／COⅡ、12S／16SrRNA、EF-1 alpha基因序列系统进化树。通过分析发现,桃蚜的COⅠ／COⅡ、12S／16S rRNA基因序列均与已知的麦双尾蚜（Diuraphis noxia（Kurdj））的相应基因序列最近,而桃蚜与麦双尾蚜的EF-1 alpha基因序列则处于相邻的分支。综合我们以前的研究分析桃蚜及其内共生菌Buchnera的系统进化关系,发现桃蚜与其内共生菌是协同进化的。     

蚜虫体内共生菌Buchnera trpB基因片段序列的测定及其系统发育分析

根据已知蚜虫的Buchnera trpB基因序列，设计了1对通用引物，通过PCR扩增法从桃蚜（Myzus persicae（Sulzer））和豆蚜（APhis craccivora Koch）体内扩增出了其内共生菌Buchnera的trpB基因，序列长度约388bp。通过对桃蚜和豆蚜体内的Buchnera trpB基因序列进行系统发育分析，结果发现桃蚜的Buchnera trpB基因序列与已知的麦双尾蚜（Diuraphis noxia（Kurdj））的Buchnera trpB基因序列相近，而豆蚜的Buchnera trpB基因序列则与已知的豌豆蚜（Acryrthosiphon pisum（Harris））的Buchnera trpB基因序列相近。这是桃蚜和豆蚜体内的trpB基因序列的首次报道。