REORGANIZATION OF MICROFILAMENTS IN PROTONEMAL TIP CELLS OF THE MOSS CERATODON PURPUREUS DURING THE PHOTOTROPIC RESPONSE
REORGANIZATION OF MICROFILAMENTS IN PROTONEMAL TIP CELLS OF THE MOSS CERATODON PURPUREUS DURING THE PHOTOTROPIC RESPONSE
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DOI：
10.1007/bf01276796
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发表时间：
1995-01-01
期刊：
影响因子：
2.9
通讯作者：
HARTMANN, E
中科院分区：
文献类型：
--
作者：
MESKE, V;HARTMANN, E
用罗丹明-鬼笔环肽染色法研究了紫斑角齿藓（Ceratodonpurpureus）茎丝顶端细胞中F-肌动蛋白的分布。重力生长的苔藓茎丝顶端细胞在其顶端具有明显的微丝排列。轴向取向的肌动蛋白束从亚顶端区域运行到顶端，在那里它们朝向尖端的中心区域会聚，尽管束不存在于中心区域本身，从而形成领状结构。在单侧红光照射的肌动蛋白链的顶端圆顶成为重新定向朝向照射的顶侧，仍然围绕着一个地区的MF，点的前瞻性生长。这一过程与膨胀的形态效应密切相关，并先于光定向生长。领状结构是管状生长形态所必需的。在黑暗中，在抗微管剂的影响下，结构被分解，肌动蛋白链沿着细胞侧翼漂移，最后聚集在随机分布的区域，在那里进一步生长。微管（MT）不参与光敏色素介导的微丝的重定向。单侧红光抑制抗微管药物的扭曲作用，并恢复具有明显光定向的领结构。相反，MT似乎负责限制细胞尖端的重定向。这一概念是基于观察到的小面积的顶端圆顶，这通常是唯一的位置的光调节MF重排，延伸到细胞的基础时，MT抑制剂施加在单侧红光照射。这又导致光导向细胞侧翼的非管状扩张。
The F-actin distribution in caulonemal tip cells of the moss Ceratodon purpureus was examined by rhodamine-phalloidin staining. Gravitropically-growing caulonemal tip cells of the moss possess a distinct alignment of microfilaments (MFs) in their apices. Axially oriented actin bundles run from subapical regions to the apex where they converge towards a central area of the tip, although bundles are absent from the central area itself thus forming a collar-like structure. During a unilateral red light irradiation the actin strands of the apical dome become reoriented towards the irradiated apical flank and still surround an area free of MFs, the point of prospective outgrowth. This process is closely correlated with the morphological effect of bulging and precedes the light-directed outgrowth. The collar structure is essential for the tubular growth form. In darkness, under the influence of antimicrotubule agents the structure is decomposed, the actin strands drift along the cell flanks and finally accumulate in randomly distributed areas where further growth takes place. The microtubules (MTs) are not involved in the phytochrome mediated reorientation of the microfilaments. Unilateral red light suppresses the distorting effect of antimicrotubule drugs and restores the collar structure with a pronounced light-directed orientation. Instead, the MTs seem to be responsible for restricting the reorientation to the cell tip. This notion is based on the observation that the small area in the apical dome, which is normally the exclusive location of the light-regulated MF rearrangement, extends towards the cell base when MT inhibitors are applied before the unilateral red light irradiation. This in turn leads to a non-tubular expansion of the light-directed cell flank.