植物学

植物学

来源出版物：Journal of Integrative Plant Biology，2014，57（5）： 349-356联系邮箱：Sodmergen，sodmergn@pku.edu.cn

封面介绍：被子植物是高等植物最为繁盛的类群，约30万种，归属于436个科，刘冰等（见本期225-231页）根据APG III系统和一些新的系统发育研究动态，对中国原产和引入的被子植物科和属进行了整理.图片显示了被子植物科级系统发育关系和花形态的多样性.（摄影、绘图：刘冰）

中国被子植物科属概览：依据APGIII系统

刘冰，叶建飞，刘夙，等

被子植物是现存高等植物最为繁盛的类群，约 30万种，是陆地植被的主要组成成分.搞清科、属和种的数量和范畴对认识全球和区域生物多样性有重要价值.分子系统学的快速发展，使很多被子植物的科和属的范畴发生了变化.本文结合APGIII系统和一些新的系统发育研究动态，对中国原产和引入的被子植物科属名单进行了整理，确认被子植物在中国原产258科，引入55科（其中6科归化），中国原产2872属，引入1605属（含归化152属），并简要介绍了中国被子植物科属范畴的历史沿革和新变化.新的名录与《中国植物志》相比，新增115科1729属，与Flora of China相比，新增85科1531属.

APG III系统；中国；分类系统；科；属；被子植物；原产；引入；归化

来源出版物：生物多样性，2015，23（2）： 225-231联系邮箱：杨永，ephedra@ibcas.ac.cn

封面介绍：The pollen tube of flowering plants delivers two sperms to the embryo sac for double fertilization. In this issue，Huang et al.（pp. 496-503）discovered dynamic changes of these gametes within the embryo sac，and found that successful double fertilization requires a one-step modification of sperm cell targeting，suggesting multiple information flows among gamete cells.

A one-step rectification of sperm cell targeting ensures the success of double fertilization

Jilei Huang，Yan Ju，Xiangfeng Wang，et al.

Successful fertilization in animals depends on competition among millions of sperm cells，whereas double fertilization in flowering plants usually involves just one pollen tube releasing two immobile sperm cells. It is largely a mystery how the plant sperm cells fuse efficiently with their female targets within an embryo sac. We show that the initial positioning of sperm cells upon discharge from the pollen tube is usually inopportune for gamete fusions and that adjustment of sperm cell targeting occurs through release and re-adhesion of one sperm cell，while the other connected sperm cell remains in stagnation. This enables proper adhesion of each sperm cell to a female gamete and coordinates the gamete fusions. Our findings reveal inner embryo sac dynamics that ensure the reproductive success of flowering plants and suggest a requirement for sperm cell differentiation as the basis of double fertilization.

Arabidopsis； double fertilization； live image； sperm celltargeting