Abstract:

The characters and ultrastructure of the intercellular connection were revealed in the outer epidermis of the garlic clove sheath by means of fluorescent probe TRITC-Phalloidin (TRITC-Ph) labeling combined with confocal laserscanning microscopy (CLSM), immuno gold labeling and transmission electron microscopy. These results show that transcellular channel is a complex of rod like cytoplasm channel and grouped plasmodesmata (PDs) in pit. The former remains a portion of the cell protoplast. The diameter of PD is normally 60-70 nm. The PDs are the real interce llular symplasmic connections of the cells. The transcellular fibers labeled with the TRITC-Ph obviously become narrow in the primary pit fields, which is the same as the characters observed under the electron microscope. The bright fluorescent spot in the primary wall reflects the grouped PDs in pit, and hence the presence of F actin in the PDs can be confirmed. In immuno gold labeling experiment, a lot of gold particles were massively distributed in the rod like cytoplasm channel and grouped PDs. The result provides effective support that these fluorescent filaments possibly are the existing form of F actin.

F肌动蛋白作为胞间连丝组分的结构与生理学证据
王冬梅¹  王学臣²   张伟成³

（1.  河北农业大学生命科学学院，保定071001；2.  中国农业大学生物学院，北京5100094；
3. 中国科学院上海植物生理生态研究所，上海200032）

摘要： 以蒜(Allium sativum L.)瓣鞘外表皮为材料,利用荧光特异探针与共焦镜检术,结合透射电镜与免疫金标记对表皮细胞间胞间联络的性质、结构进行了系统观察.结果表明,加厚壁上的通道是由狭长的管状胞质和初生纹孔场上成束的胞间连丝衔接组成,前者实为原生质体的一部分.单个胞间连丝的孔径为60～70 nm,属正常胞间连丝范围,它们乃相邻细胞间共质联系的所在.荧光探针TRITC-Phalloidin (TRITC-Ph)标记的结果显示,整个通道上呈现红色荧光的纤索在接近初生纹孔场处明显变窄,与超微结构观察中所见的结构特点相吻合,共焦镜下观察到的初生壁上的荧光亮斑乃初生纹孔场中成束胞间连丝被标记的反映,从而有效地证实了F肌动蛋白在常态胞间连丝上的存在.免疫金标记实验显示在管状胞质中和胞间连丝上有金颗粒分布,这一结果为证实荧光标记物具肌动蛋白性质提供了有说服力的补充.

关键词： 胞间连丝；F-肌动蛋白；共焦激光扫描镜检术；超微结构；蒜

Key words: plasmodesmata, F-actin, confocal laser scanning microscopy (CLSM), ultrastructure, Allium sativum