毛竹茎秆纤维发育过程中Ca^(2+)分布的时空变化

Dynamic changes of Ca^(2+) distribution during the development of fiber in Phyllostachys edulis culms

利用焦锑酸盐沉淀技术,对毛竹茎秆纤维发育过程中Ca2+的时空变化进行了研究。在纤维原始细胞发育期,Ca2+主要分布在细胞壁和细胞核染色质中;随着初生壁的形成,大量的Ca2+在液泡膜内侧成稀疏点状分布,在吞噬泡和降解的细胞质中出现Ca2+反应颗粒的沉积,液泡内逐渐出现大量的絮状Ca2+沉积,在细胞核和细胞壁上没有Ca2+分布;随后细胞质中Ca2+大量聚集,少量Ca2+沿液泡膜内侧分布,而液泡中Ca2+含量变得极少,在细胞壁、胞间连丝和细胞核中几乎没有Ca2+分布;随着次生壁的形成,胞质内的Ca2+浓度增加,并随着次生壁的逐渐加厚而聚集成块状;在次生壁形成的整个过程中,在降解的细胞质、凝聚的染色质、纹孔和运输小泡膜上一直存在Ca2+。结果表明:Ca2+参与了毛竹茎秆纤维细胞的增殖过程和细胞壁的整个形成过程;胞质Ca2+的内流是引起纤维细胞PCD的重要原因之一,并参与了PCD过程中原生质体的降解。

The dynamic changes of Ca^2＋ distribution during the development of fiber in Phyllostachys edulis culms was studied using a potassium pyroantimonate precipitation method. At the stage of fiber initials formation, Ca^2＋ mainly distributed on the cell wall and chromatin of nucleus. With the formation of fiber primary wall formation, some Ca^2＋ appeared sparsely in the inner side of tonoplast, and some Ca^2＋ also was observed in phagosome and vacuole, but little was seen in nucleus and cell wall. Afterwards, a great deal of Ca^2＋ assembled in the cytoplasm, but the concentration of Ca^2＋ in vacuole decreased, and Ca^2＋ was yet not present in cell wall and nucleus. With the formation of secondary wall, the level of Ca^2＋ in the cytoplasm of fiber increased. Furthermore, Ca^2＋ congregated densely in fiber cytoplasm with the thickening of secondary wall. During the secondary wall formation, Ca^2＋ persisted in the disintegrated cytoplasm, agglutinated chromatin and pit channel and transfer vesicles. The results demonstrated that Ca^2＋ was involved in the proliferation of fiber and the whole formation of fiber wall, and the congregation of Ca^2＋ in cytoplasm may be one of reason bringing the PCD of fiber, and Ca^2＋ played functions in the disintegration of protoplast during fiber PCD.