牛角瓜大小孢子发生及雌雄配子体发育研究  

Study on the Megasporogenesis,Microsporogenesis and Development of Female and Male Gametophytes of Calotropis gigantea L.

作　　者：刘鹏[1] 张太奎[1] 李璐[1] 刘婷[1] 王连春[1] 罗明灿[1] 刘惠民[1] 

机构地区：[1]西南林业大学林学院,昆明650224

出　　处：《西北植物学报》2016年第1期48-58,共11页Acta Botanica Boreali-Occidentalia Sinica

基　　金：林业公益性行业科研专项(201304810)

摘　　要：为从胚胎学方面解释牛角瓜坐果率低的原因,该实验以牛角瓜(Calotropis gigantea L.)不同时期的新鲜花朵为试材,采用石蜡切片法,观察牛角瓜大小孢子发生及雌雄配子体发育过程。结果显示:(1)牛角瓜小孢子孢原细胞起源于表皮细胞下面的分生组织并在两个地方分化;花药壁由外向内由1层表皮、1层药室内壁、2层中层和1层绒毡层组成,花药壁发育属于基本型,绒毡层属于分泌型;小孢子形成时胞质分裂方式为连续型,成熟花粉粒为3-细胞型复合花粉,有2个较小的精细胞和1个较大的营养细胞,精细胞呈凸透镜型。(2)牛角瓜的雌蕊具有2心皮,子房1室,边缘胎座,胚珠倒生,单珠被,薄珠心;大孢子母细胞由1个孢原细胞直接发育而成,合点端大孢子分化成为功能大孢子,由功能大孢子发育为7细胞8核的蓼型胚囊。(3)牛角瓜雌蕊发育晚于雄蕊,花蕾开放前雌雄蕊发育趋于同步。研究表明,虽然在雌雄配子体发育过程中存在败育现象,但大部分雌雄配子体发育正常。To observe megasporogenesis,microsporogenesis and development of female and male gametophytes,we studied the fresh flowers of Calotropis gigantea using paraffin wax.The results were as follows：（1）Archesporial cell of C.gigantea microspore differentiated from two areas of subcutaneous tissue.The mature anther wall was composed of epidermis,endothecium（1layer）and middle layer（2layers）,glandular tapetum（1layer）and its development model belonged to basic type.The glandular tapetum was a secretory structure.Cytokinesis of microspore mother cells was continuously split twice.Three cells were observed in the mature pollen grain：2small sperm cells and one large vegetative cell.（2）C.gigantea had two carpels in pistil and 1locule in ovary.The ovule was anatropous,marginal placentation,unitegmic and tenuinucellus.The megaspore tetrads were linear and the chalazal megaspore was functional.The mature embryo sacs had seven cells with eight nucleis,and belonged to polygonum type sac.（3）C.gigantea pistil developed later than stamen,and the female and stamen developed synchronized before buds open.It was considered that the barrenness of C.gigantea was not due to male or female sterility,although some proportional abortion exists in the development of pistil and stamen.Maybe it was related to pollination fertilization.

关 键 词：牛角瓜 大小孢子发生 雌雄配子体发育 

分 类 号：Q944.58[生物学—植物学]