共轭置换子群与有限群的可解性

 利用共轭置换子群的概念来研究有限群的可解性问题，获得了一个群为可解群的若干新刻画.特别，得到了:① 若M<·G，且M的极大子群均在G中共轭置换，则G可解；② 设群G无截断PSL2(7)，M<·G，且|G:M|=pα，若M的2-极大子群均在G中共轭置换，则G可解.

Outcrossing rates analysis of three Amomum species in Zingiberaceae

Flexistyly is a novel flowering strategy occurring i n ginger family (Zingiberaceae)． It is an unique and “active” floral dimorphi sm achieved by both changing the position of the stigma and separating the maturat ion of male and female organs in different times during anthesis． In this resea rch, outcrossing rates of two species (Amomum maximum and A． putrescens ) with flexistyly and one species (Avillosum) without flexistyly were co mpared using allozyme experiments． The results show that the outcrossing rates of flexistylous species are significantly higher than that of the species withou t flexistyly． Moreover, within the natural populations of flexistylous species, outcrossing rate of anaflexistylous morphs are higher than that of cataflexisty lous morphs． These findings demonstrate that flexistyly may play an effective r ole to promoting outcrossing．