Double Fertilization in Arabidopsis thaliana Involves a Polyspermy Block on the Egg but Not the Central Cell

作     者：Rod J. Scott Susan J. Armstrong James Doughty Melissa Spielman 

作者机构：Department of Biology and Biochemistry University of Bath Claverton Down Bath BA2 7AY United Kingdom School of Biosciences The University of Birmingham Edgbaston Birmingham B15 2TT United Kingdom 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2008年第1卷第4期

页      面：611-619页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 0901[农学-作物学] 0902[农学-园艺学] 0713[理学-生态学] 

基　　金：Biotechnology and Biological Sciences Research Council BBSRC 

主　　题：Double Fertilization Arabidopsis thaliana Involves Polyspermy Block Central Cell 

摘      要：In animal reproduction, thousands of sperm may compete to fertilize a single egg, but polyspermy blocks prevent multiple fertilization that would otherwise lead to death of the embryo. In flowering plants, successful seed development requires that only two sperm are delivered to the embryo sac, where each must fertilize a female gamete （egg or central cell） to produce the embryo and endosperm. Therefore, polyspermy must be avoided, not only to prevent abnormalities in offspring, but to ensure double fertilization. It is not understood how each sperm fertilizes only one female gamete, nor has the existence of polyspermy barriers been directly tested in vivo. Here, we sought evidence for poly- spermy blocks in angiosperms using the polyspermic tetraspore （tes） mutant of Arabidopsis, which allows in-vivo challenge of egg and central cell with multiple male gametes. We show that tes mutant pollen tubes can transmit more than one sperm pair to an embryo sac, and that sperm from more than one pair can participate in fertilization. We detected endosperms but not embryos with ploidies that could only result from multiple fertilization. Our results therefore demonstrate an in-vivo polyspermy block on the egg, but not the central cell of a flowering plant.