Floral development in the androdioecious tree Tapiscia sinensis:Implications for the evolution to androdioecy  

作　　者：Gui-Liang Xin Guo-Lun Jia Xiao-Long Ren Yue-Yue Wang Peng Zhao Wen-Zhe Liu 

机构地区：[1]Key Laboratory of Resource Biology and Biotechnology in Western China(Northwest University),Ministry of Education,School of Ufe Sciences,Northwest University,Xi'an 710069,China

出　　处：《Journal of Systematics and Evolution》2021年第1期183-197,共15页植物分类学报（英文版）

基　　金：We thank Dr.Xin Zhang and Dr.Yafu Zhou for their constructive suggestions and technical support.This work was supported by the National Natural Science Foundation of China(Grant No.31770413).

摘　　要：The evolutionary pathway between hermaphroditism and dioecy(females and males in a single population)draws widespread interests,and androdioecy(bisexuals and males in a single population)is rarely achieved as an intermediate state between the two breeding systems.Flower bud differentiations in the pistils of hermaphrodites and the pistillodes of males in androdioecious Tapiscia sinensis Oliv.are investigated by routine paraffin section technology,light microscopy,and scanning electron microscopy.A phylogenetic approach is used to analyze the origin of androdioecy.In T.sinensis,hermaphroditic flowers(HF)and male flowers(MF)experienced a similar development pattern in early flower bud differentiation,including the initiation of tepals and stamens.However,the carpel differenNation of MF and HF proceed in different patterns.In HF,the central zone bulges out and produces a ring meristem on which two to three carpel primordia emerge,which eventually developed into a normal pistil with a stigma,a style,and an ovary.However,in most MF,vestigial pistils are stemlike(type Ⅰ),and very few have an empty ovary(type Ⅱ)or a sterile ovule(type Ⅲ).Moreover,the evolution of sexual systems within the Huerteales indicates that hermaphroditism is the primitive character of T.sinensis.Tapiscia sinensis shows different degrees of reduction between male flowers and bisexual ones in the evolution to dioecy.Functional androdioecy originated from a hermaphroditic ancestor in T.sinensis and,as an intermediate sexual system,involves evolution from hermaphrodites to dioecy.

关 键 词：androdioecious system floral dimorphism sexual evolution Tapiscia sinensis 

分 类 号：Q945[生物学—植物学]