Ovule morphogenesis and structure in Menispermaceae,focusing on the development of the single fertile ovule and its systematic significance  

作　　者：Lu Wang Xiao-Ling Yan Xiao-Hui Zhang Yi Ren 

机构地区：[1]College of Life Sciences,Shaanxi Normal University,Xi'an 710062,China [2]Shanghai Chenshan Plant Science Research Center,Chinese Academy of Sciences,Chenshan Botanical Garden,Shanghai 201602,China

出　　处：《Journal of Systematics and Evolution》2021年第3期581-595,共15页植物分类学报（英文版）

基　　金：The project was funded by the National Natural Science Foundation of China(Nos.31770203,31100141,and 31770200).

摘　　要：Menispermaceae is one of the core groups of Ranunculales.The single fertile ovule in each ovary in Menispermaceae varies greatly in integument number,micropyle formation,and integument lobe.However,data regarding ovule morphogenesis in the family are very limited.In this study,we document ovule development of selected species in the Menispermaceae using scanning electron microscopy and light microscopy.Ovule development in Menispermaceae shows the following characteristics.Two ovules are initiated in a young carpel,one of them degenerates gradually and the other develops into a fertile ovule in subsequent stages.Bitegmic in Sinomenium Diels.and Cocculus DC.and unitegmic in Stephania Lour.The formation of unitegmy is probably due to integumentary shifting.The annularly initiated inner integument is of dermal origin and has 2–3 cell layers in the family,but the semi-annularly initiated outer integument is of both dermal and subdermal origin.Both inner and outer integument are cup-shaped at maturity.The cup-shaped outer integument is formed due to the outer integument's extension to the concave(adaxial)side of the funiculus.The obturator is well developed and consists of 2–3 cell layers in Cocculus or 9–11 cell layers in Stephania.Ovule development of Menispermaceae suggests some common characteristics between Cocculus and Sinomenium,and derived unitegmy supports molecular data that indicate Stephania is one of the late-diverging lineages in the family.Integument lobations are present.The sterile ovule shows variations in the degeneration process.These results will provide evidence for exploring the evolution of ovules in Ranunculales.

关 键 词：Cocculus INTEGUMENT MENISPERMACEAE OBTURATOR ovule development RANUNCULALES Sinomenium Stephania 

分 类 号：Q94[生物学—植物学]