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 in ginger family (Zingiberaceae)． It is an unique and “active” floral dimorphismachieved by both changing the position of the stigma and separating the maturation of male and female organs in different times during anthesis． In this research, outcrossing rates of two species (Amomum maximum and A． putrescens) with flexistyly and one species (Avillosum) without flexistyly were compared using allozyme experiments． The results show that the outcrossing rates of flexistylous species are significantly higher than that of the species without flexistyly． Moreover, within the natural populations of flexistylous species,outcrossing rate of anaflexistylous morphs are higher than that of cataflexistylous morphs． These findings demonstrate that flexistyly may play an effective role to promoting outcrossing．