陆地棉珠孔的结构及花粉管在其中的生长途径

在大多数被子植物中，花粉管经珠孔进入胚珠进而实现受精，但珠孔结构及花粉管在其中的生长途径是植物受精生物学研究中较薄弱的一个环节。迄今仅在向日葵中从超微结构水平上作了详细的研究［１］，因而需要扩大研究的对象。陆地棉花粉管生长所经雌蕊组织中，关于柱头、花柱［２，３］、珠心［４，５］和助细胞［６］的超微结构已有较详细的研究，但涉及珠孔这一环节，只有简单的描述［７］。本文报道我们在这方面的研究结果。材料和方法取陆地棉（ＧｏｓｓｙｐｉｕｍｈｉｒｓｕｔｕｍＬ．）授粉前和授粉后２２小时的胚珠，切除其合点端部分…

STRUCTURE OF MICROPYLE IN GOSSYPIUM HIRSUTUM AND THE PATHWAY OF POLLEN TUBE GROWTH

The micropyle of Gossypium hirsutum consists of an exostome and an endostome.On semithin serial transections, the exostome was visualized as a branched narrow gap except its outer and inner openings, whereas the endostome only a narrow linear gap. Ultrastructurally, the micropyle gap was formed by the integumental epidermal cells coated with a cuticle.The cells lining the micropyle gap were characterized by a large nucleus and abundant organelles as mitochondria, plastids, rough endoplasmic reticulum, vesicle secreting dictyosomes and small vacuoles.One or two pollen tubes were seen growing through the exostome and endostome gaps.Thus, the micropyle in cotton was basically a closed type as has been found in sunflower, but similar asymmetrical structural features were not observed.