水涝胁迫下海滨锦葵幼苗根尖细胞内Ca^(2+)分布与变化

Distribution and Variation of Ca^(2+) in Root Apical Cells of Kosteletzkya virginica(L.) Seedlings under Waterlogging

采用醋酸双氧铀染色与透射电镜技术,以海滨锦葵为试验材料,连续观测水涝胁迫下及涝后恢复期间海滨锦葵根尖细胞内Ca^(2+)的分布与变化特性。结果显示:随着水涝时间延长,海滨锦葵根尖细胞间隙与细胞核、液泡中钙离子沉积密度逐步降低,质体外膜上存在Ca^(2+)分布,但低于对照组,而Ca^(2+)向细胞质移动,在局部区域聚集,导致细胞质钙离子增加。水涝去除20 d后,细胞壁中出现钙离子沉积,细胞间隙、质体外膜上与液泡中所分布钙离子增加,细胞质所聚集的Ca^(2+)逐步分散,基本不存在Ca^(2+)沉积。研究认为,水涝胁迫下,海滨锦葵根尖细胞内Ca^(2+)浓度迅速上升;涝后恢复期间,Ca^(2+)浓度逐渐下降,起着外界信号传递的作用。

With Kosteletzkya virginica （ L. ）, we observed its distribution and variation of Ca^2＋ in root apical cells continuously by transmission electron microscope combined with uranyl acetate staining method in and after waterlogging stress. During waterlogging, Ca^2＋ of root apical cells mainly distributed within intercellular spaces, nuclei and vacuoles, but the density of Ca^2＋ reduced gradually. Additionally, there were calcium ions located on outer membranes of plastids, but its density was lower than that in control within this stress. However, Ca^2＋ showed a trend to move into cytoplasm, and accumulated to in some areas. On the 20 th day after drainage of waterlogging, the amassed calcium ions released, and almost no Ca^2＋ distributed in cytoplasm. However, with the release of cytoplasm Ca^2＋, the densities of calcium ions were increased in intercellu- lar space, vacuoles and outer membrane of plastid, a great deal of Ca^2＋ located with cell walls in recovery period. After 20 days of recovery, the distribution of Ca^2＋in waterlogged plants was similar to that in control ones. The density of Ca2. in root apical cell was increased quickly in waterlogging and subsequently decreased in restoration, and Ca^2＋ not only affected cell function, but also acted as a means to transmit outside information in K. virginica plants.