陆地棉雌蕊的花粉管生长途径中钙分布的超微细胞化学定位

用焦锑酸盐沉淀法对陆地棉(Gossypium hirsutum L.)授粉前后的柱头、花柱、珠孔与珠心组织中的钙进行了超微细胞化学定位。X射线波谱与能谱分析证明所定位的沉淀确系焦锑酸钙。观察结果表明:在整个花粉管生长途径中的雌蕊组织,钙分布均较其它相邻组织密集;钙主要分布在细胞壁与胞间基质等质外体系统中。在雌蕊中生长的花粉管,其尖端细胞器区也有丰富的钙。

ULTRACYTOCHEMICAL LOCALIZATION OF CALCIUM IN THE POLLEN TUBE TRACK OF COTTON GYNOECIUM

Cotton (Gossypium hirsutum L.) stigma, style and ovule segments were fixed pre-and post-pollination in glutaraldehyde and osmium solutions containing potassium pyroantimonate, processed with conventional dehydration and infiltration procedure, and embedded in Epon 821 resin. To identify the element constitution of the pyroantimonate deposits in the samples, wave-and energy-dispersive X-ray microanalyses were employed, and it was confirmed that the deposits were truly calcium pyroantimonate. Transmission electron microscopic observations revealed that the deposits were more abundant at the whole pollen tube track as compared with the adjacent tissues. They were mainly localized in the apoplast system, i. e. the intercellular matrix of the stigmatic tissue, the outer cell wall layers of stylar transmitting tissue, the intercellular openings and gaps of micropyle, and the degenerated column of nucellus. It was reported that these apoplast spaces were just the positions where pollen tubes grew. The pollen tube tip growing in the micropyle was also rich in calcium, which was especially localized at the new wall, vesicles and mitochondria. All these observations suggested that calcium in the gynoecium tissues may play an suggested important role in the pollen tube growth in situ.