异叶苦竹花粉管生长及双受精过程

以异叶苦竹为材料,采用扫描电镜、荧光显微镜技术及传统的石蜡制片技术,解剖观察其花粉管生长途径及双受精过程。结果表明:(1)授粉后,花粉在柱头上吸水膨胀,约30 min即可萌发。(2)授粉1～2 h后花粉管可达到花粉长度的5～10倍,花粉管在柱头分支中进一步伸长,并开始伸入花柱中生长。(3)授粉后5 h,大量花粉管沿引导组织进入花柱基部与子房顶部之间的子房壁,有少量花粉管在子房壁与外珠被之间的缝隙中生长。(4)授粉后8 h,少量花粉管到达珠孔端。(5)授粉后15～18 h,精核与极核融合,形成初生胚乳核;精、卵核融合,形成合子。(6)授粉后20～30 h,仍可在花柱中见到大量呈束状的花粉管。(7)授粉后48 h,子房内的大部分花粉管出现解体,大多数花粉死亡。研究认为,精细胞到达胚珠的时间为8 h。

Characteristics of Pollen Tube Growth and Double Fertilization in Arundinaria simonii f.heterophylla(Bambusoideae)

Pollen tube growth and double fertilization have profound effects on seed production.Bamboo plants usually have a relatively long vegetative growth,so it is not easy to have the opportunities to study their reproductive characteristics.In this article,characteristics of pollen tube growth and double fertilization in the florets of Arundinaria simonii f.heterophylla were investigated.The main results are shown as follows:(1)30 minutes after pollination,almost all pollens of A.simonii f.heterophylla germinated on the stigma;(2)pollen tubes entered style in 1-2 h;(3)5 hours after pollination,a lot of pollen tubes bundles formed and a few pollen tubes grew along the intercellular spaces in the pistil;(4)8 hours after pollination,pollen tubes entered micropyle;(5)15-18 hours after pollination,two sperm nuclei fused with egg nucleus and polar nucleus separately,forming the zygote and the primary endosperm nuclei separately;(6)20-30 h after pollination,most pollen tubes were still observed in the pistil;(7)2 days after pollination,pollen tubes disintegrated and most of the pollen grains died.The time for sperms to reach the micropyle from the stigma is about 8 hours.