毛白杨花粉败育过程中胼胝质的异常分布变化

摘要

The callose deposition in the process of microsporogenesis of Populus tomentosa Carr.male fertile clone 1319 and sterile stub BM-1 was investigated by staining with aniline blue.In fertile anthers,callose deposition occurs at the corners of the microspore mother cells,and then at the dyad and tetrad stage a thick callose wall locates in the cells plate and cells surrounding.With the dissolution of the callose wall,microspores are released into the chamber,and there is little callose around the free microspores.At the mature pollen stage,with tapetum disintegration,endothecium thickning and chamber cracking,callose distributes in the residual tapetum and endothecium.Compared with its counterpart,callose synthesis in BM-1 anthers decreases and callose distribution shows obvious abnormality.No callose appeares in sterile anther during the microspore mother cell period.At the dyad and tetrad stage,callose mainly deposits in the cells plate but less around the dyads and tetrads.With the development of the microspore to mature pollen,the callose deposits in the tapetum significantly,but not in the endothecium.Ultrastructural observation with transmission electron microscopy showed normal development in 1319 and abnormal development in BM-1 pollens.Therefore,the abnormal synthesis and distribution of callose is one of the reasons for pollen abortion of P.tomentosa Carr.%采用苯胺蓝染色的方法,对育性良好的无性系1319及花粉败育雄株BM-1的花药发育过程中胼胝质的分布及变化进行了观察.结果表明,育性良好的花药中,胼胝质首先在小孢子母细胞角隅处沉积；随后,较厚的胼胝质壁分布于四分体细胞间以及细胞周围,随着胼胝质的解体,小孢子释放到药室中,游离小孢子外围无明显胼胝质分布;小孢子发育形成成熟花粉,花药绒毡层解体,内壁加厚开裂,胼胝质分布于残留的绒毡层以及内壁.与育性良好的花药相比,败育花药的胼胝质合成量减少并呈现明显分布异常.小孢子母细胞时期无明显胼胝质合成;胼胝质主要沉积于四分体细胞间且细胞外围胼胝质分布量减少；小孢子发育至成熟花粉,药室绒毡层沉积较多胼胝质而内壁无明显胼胝质分布.透射电镜结果显示,毛白杨无性系1319花粉外壁发育正常,而毛白杨不育雄株BM-1仅产生少量饱满花粉,且其花粉外壁发育不完全.从而说明胼胝质的异常合成与分布是毛白杨花粉败育的原因之一.