韭发育雌配子体中Ca^(2+)分布特征

The Characteristic of Calcium Distribution in Developing Female Gametophyte of Allium tuberosum

对韭开花前1 d到开花后2 d的发育胚囊中Ca2+分布特征进行研究,结果显示:在开花前1 d游离核胚囊形成细胞,Ca2+主要分布在极核周围的细胞质小液泡中,与中央细胞的大液泡形成有关;在开花当天,卵细胞大液泡体中Ca2+增多,与其大液泡形成有关;开花后1 d,卵细胞大液泡中钙沉淀颗粒减少,助细胞珠孔段的Ca2+增多,合点端较少,呈极性分布;开花后2 d,卵细胞大液泡和中央细胞大液泡珠孔部位Ca2+再次明显增加。助细胞珠孔端丝状器中Ca2+也增加,一个助细胞退化,呈现接受花粉管状态。韭发育胚囊中Ca2+分布特征显示其参与调控胚囊细胞的分化,揭示雌配子体中Ca2+分布的时空特征是深入研究胚囊细胞分化的基础。

Characteristic of Ca^2＋ distribution in developing female gametophyte of Allium tuberosum was studied from 1 d before anthesis to 2 d a fter anthesis. At 1 d before anthesis, the nuclear embryo sac differentiates gametophyte cells. Calcium precipitates of young embryo sac were few and mainly located in the small vacuoles surrounding polar nuclei, suggesting Ca^2＋ relating with the formation of the large vacuole of central cell. At anthesis, the precipitates in large vacuole of egg increased, also suggesting Ca^2＋ relating with formation of the large vacuole of egg cell. At 1 d after anthesis, the precipitates in egg cell decreased and increased in synergid cells, in which the precipitates displayed polarity distribution： more in the micropyle end of the cell than in the chalazal end. At 2 d after anthesis, the precipitates in the large vacuole of egg and the micropyle part of central cell appeared again. The precipitates in filiform apparatus of both synergids also increased. One synergid cell degenerated, which prepared to accept pollen tube. The characteristic of calcium distribution in developing embryo sac of A. tuberosum suggests that Ca^2＋ may regulate cell differentiation of embryo sac. Exploring the spatial-temporal feature of Ca^2＋distribution in developing embryo sac is a base of further study of cell differentiation of embryo sac.