Ovular development and perisperm formation in Phytolacca americana (Phytolaccaceae) and their systematic significance in Caryophyllales  

作　　者：Hong-Chun ZHENG Sheng-Wen MA Tuan-Yao CHAI 

机构地区：[1]College of Life Science, Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Journal of Systematics and Evolution》2010年第5期318-325,共8页植物分类学报（英文版）

基　　金：the National High Technology Planning Program of China for its support(Grant Nos.2007AA021404 and 2006AA10Z407)

摘　　要：Phytolacca is the biggest and most original genus in Phytolaccaceae and an important genus in plant systematic studies. Light microscopy results show that the Phytolacca americana L. ovule arises from the caulis （floral receptacle）. The perisperm and hypostase are simultaneously initiated from the top several layers of cells of chalaza after fertilization, and the perisperm is located between the nucellus and hypostase. In the early stages of development, the hypostase cells are thin-walled with dense cytoplasm, clear nuclei, and some reserve granules. Later, at the heart-shaped embryo stage, the hypostase cells are dead and thick-walled. The main functions of the hypostase may be to maintain cellular division and perisperm growth without delivering nutrient materials to the perisperm. An evolutionary picture of placentation in Caryophyllales is also presented.Phytolacca is the biggest and most original genus in Phytolaccaceae and an important genus in plant systematic studies. Light microscopy results show that the Phytolacca americana L. ovule arises from the caulis （floral receptacle）. The perisperm and hypostase are simultaneously initiated from the top several layers of cells of chalaza after fertilization, and the perisperm is located between the nucellus and hypostase. In the early stages of development, the hypostase cells are thin-walled with dense cytoplasm, clear nuclei, and some reserve granules. Later, at the heart-shaped embryo stage, the hypostase cells are dead and thick-walled. The main functions of the hypostase may be to maintain cellular division and perisperm growth without delivering nutrient materials to the perisperm. An evolutionary picture of placentation in Caryophyllales is also presented.

关 键 词：hypostase NUCELLUS OVULE perisperm Phytolacca placentation. 

分 类 号：S794.1[农业科学—林木遗传育种] Q943[农业科学—林学]