植物學(xué)

植物學(xué)

來源出版物：Journal of Integrative Plant Biology，2014，57（5）： 349-356聯(lián)系郵箱：Sodmergen，sodmergn@pku.edu.cn

封面介紹：被子植物是高等植物最為繁盛的類群，約30萬種，歸屬于436個科，劉冰等（見本期225-231頁）根據(jù)APG III系統(tǒng)和一些新的系統(tǒng)發(fā)育研究動態(tài)，對中國原產(chǎn)和引入的被子植物科和屬進(jìn)行了整理.圖片顯示了被子植物科級系統(tǒng)發(fā)育關(guān)系和花形態(tài)的多樣性.（攝影、繪圖：劉冰）

中國被子植物科屬概覽：依據(jù)APGIII系統(tǒng)

劉冰，葉建飛，劉夙，等

被子植物是現(xiàn)存高等植物最為繁盛的類群，約 30萬種，是陸地植被的主要組成成分.搞清科、屬和種的數(shù)量和范疇對認(rèn)識全球和區(qū)域生物多樣性有重要價(jià)值.分子系統(tǒng)學(xué)的快速發(fā)展，使很多被子植物的科和屬的范疇發(fā)生了變化.本文結(jié)合APGIII系統(tǒng)和一些新的系統(tǒng)發(fā)育研究動態(tài)，對中國原產(chǎn)和引入的被子植物科屬名單進(jìn)行了整理，確認(rèn)被子植物在中國原產(chǎn)258科，引入55科（其中6科歸化），中國原產(chǎn)2872屬，引入1605屬（含歸化152屬），并簡要介紹了中國被子植物科屬范疇的歷史沿革和新變化.新的名錄與《中國植物志》相比，新增115科1729屬，與Flora of China相比，新增85科1531屬.

APG III系統(tǒng)；中國；分類系統(tǒng)；科；屬；被子植物；原產(chǎn)；引入；歸化

來源出版物：生物多樣性，2015，23（2）： 225-231聯(lián)系郵箱：楊永，ephedra@ibcas.ac.cn

封面介紹：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