宁夏枸杞柱头和萌发花粉中钙分布特征

用焦锑酸钾沉淀法对宁夏枸杞柱头和花粉中的钙离子分布进行了研究.结果显示,宁夏枸杞柱头表皮有一覆盖层,其中有许多含钙沉淀颗粒的小泡,当花粉落到柱头后从覆盖层中吸水,在萌发孔的表面上聚集了较多的钙沉淀颗粒.同时,花粉内部出现许多含钙的小液泡,使花粉体积增大,内部产生膨压,花粉萌发;生长在覆盖层中的花粉管顶端穿过覆盖层小泡时,附近聚集了较多的钙沉淀颗粒,在花粉管壁上也附着较多的细小钙沉淀颗粒.萌发的花粉粒中由大液泡占据,在其亚顶端的细胞质中,聚集较多钙沉淀颗粒的线粒体膨大形成了一些含钙沉淀颗粒的小液泡,由这些小液泡融合形成的大液泡,将花粉管细胞质挤到其顶端,使其极性生长.这是首次发现在植物柱头覆盖层中有钙离子的现象,从体内证明了钙离子在花粉萌发过程中的现象.讨论了枸杞柱头组织中钙的分布和花粉管的萌发与生长的关系.

Calcium Distribution in the Stigma and Germinating Pollen of Lycium barbarum

The stigma of Lycium barbarum is wet type and some material to be secreted to the surface of stigma to form a layer of tectum at anthesis.There were many vesicles in the tectum and numerous calcium precipitated grana were accumulated in the tectum vesicles.When pollen grains landed onto the stigma they began to hydrate and form many small vacuoles in which some calcium precipitated grana located,which made a swelling pressure in pollen.During pollen germinating in the tectum,the pollen tubes often traversed tectum vesicles and displayed many calcium precipitated grana on the tube wall,suggesting it to absorb calcium of the tectum vesicles.In the base of pollen tube some mitochondria with calcium precipitated grana swelled to form small vacuoles which fused to form a large vacuole.The pollen tube cytoplasm was pushed into the top of tube to make sure directional growth.This is first time to report that stigma tectum containing rich calcium in flowering plants.The calcium distribution in the stigma and pollen germination and tube growth were also discussed.