洋葱鳞茎薄壁细胞原生质体胞质肌动蛋白质微丝骨架的形态与结构

MORPHOLOGY AND STRUCTURE OF CYTOPLASMIC ACTIN MICROFILAMENT SKELETON IN ONION PROTOPLASTS OF BULB PARENCHYMA CELLS

使用四甲基罗丹明标记的鬼笔环碱(TRITC-Ph)探针,以新分离的洋葱鳞茎薄壁细胞原生质体为材料,观察了细胞胞质肌动蛋白微丝骨架的结构与形态。研究结果发现洋葱鳞茎内部细胞的细胞质内存在极丰富而精细的肌动蛋白微丝束。这些肌动蛋白微丝束的直径约1.0—4.5μm,有下列四种不同的排列形式:(1)相互平行排列,方向大体与细胞的长轴垂直;(2)从一些结合位点辐射而出,并向四周延伸,然后再相互交织在一起,形成一个非常密集而复杂的网络;(3)细而稀疏,相互交织成网状,两端分别与质膜不同位置上的结合位点相连;(4)粗而稀疏,相互交织成网状,两端都与质膜相连,或一端与质膜相连,另一端与细胞核周围的微丝束网络相连。部分微丝束具有“Y”形分支。

Cytoplasmic actin microfilament systems were localized in the freshly isolated onion protoplasts of bulb parenchyma cells using TRITC labelled phalloidin probe in the present study. It was found that the cytoplasm of the protoplasts were rich in very dense and fine actin microfilament cables (AMCs). The AMCs were 1.0-4.5 μm thick and showed the following four different arrangements: (1) The AMCs were parallel to each other and run in the direction perpendicular to the longitudinal axis of a cell; (2) The AMCs stretched out and elongated around from some combining sites and then intertwined together, by which a very dense and complicated network was formed; (3) The AMCs were thinner in diameter and less dense and intertwined with each other into a network. And their two ends were in connection with the combining sites on different regions of plasmalemma; (4) The AMCs were thicker in diameter and less dense and also intertwined into a network, but a part of them had Y shaped branchs and connected with the perinuclear AMC network and the combining sites on the plasmalemma by their two ends.