Study On The Abnormal Developing Pollen Of Hermaphroditic Flowers From Tapiscia Sinensis (Tapisciaceae)

Tapiscia sinensis (Tapisciaceae) is a functional androdiecy species, a perennial deciduous woody; male and hermaphroditic individtlals coexist in the population,and respectively produce male and hermaphroditic flowers.Lately,scholars have accomplished the study on taxology, ecology, anatomy and morphology, geobotany,reproduetive biology and fruit overwintering strategy about Tapiscia sinensis.Functional androdiecy is the rarest breeding system in angiosperms, functional male individtlals and functional hermaphroditic individtlals coexist in the population.Maintenance of androdioecious reproductive system need male reproductive fitness of males leastways have twice advantage than hermaphroditeThe males of Tapiscia sinensis present an advantage of male reproductive fitness in many aspects, such as the number of flowers in the inflorescence, counts of pollen, pollen viability and pollen germination capacity. For example, pollen viability of males is about 10.8 times higher than hermaphrodite. But it’s still not clear that reason about the difference between males and hermaphrodite.This paper, from the microscopic and ultrastructural level,the methods of cytology, cytochemistry and molecular biology were used to research the process of the development of anthers and male gametophyte,and dynamic change of polysaccharides in anther.Trying to ascertain the following main issues:①The microscopic and ultrastructural characteristic of anther wall, microsporogenesis and male gametogenesis.② Dynamic change of polysaccharide accumulation and translocation in the anther③The cause about weak male fertility of hermaphrodite of Tapiscia sinensis. The results show:(1)The process of development of Tapiscia sinensis anther is divided into 12 stages. Development of males anthers is normal.During these stages,involving a variety of cellular processes,including growth and degradation of anther wall,microsporogenesis,male gametogenesis, anther dehiscence and so on. After stage 8, cells of anther wall occur programmed cell death (PCD) gradually, in order to provide the necessary nutrients for pollen development. Stages 1-8 of hermaphroditic flower are same to male flowers. Differences in development of anther between males and hermaphrodite became apparent at late stage 9.(2) During processes development of anther, there are two peak of polysaccharide accumulation, respectively at stages6-9 and 9-11.But there’s a lack of the second peak in the hermaphroditic flowers. After stage 9,abnormal abundant polysaccharide were stored in the cells of connective tissue, which suggested that the function of plant transporting polysaccharide into anther is normal but polysaccharides don’t transported into anther chamber and supply nutrient substance for microspores. There are no polysaccharide in the cells of anther wall and microspores, all the time.Because of decreasing resources, development of microspores are abnormal, and even microspore occur degenerate. The DAPI-TUNEL assay also show that microspore occur programmed cell death (PCD).Finally, abnormal structure and lowly viability of pollen were observed from the hermaphroditic flower anthers.In summary:in male flowers, development of anther is normal, but in anther of hermaphroditic individuls, metabolism of nutrients exist abnormal, nutrients for microspore greatly reduced. Because of diminishing nutrients, development of microspores are abnormal, and even microspore occur degenerate. Finally, pollen that produced by hermaphroditic individuals, have abnormal structure and lowly viability.