薄荷盾状腺毛分泌过程的超微结构研究

ULTRASTRUCTURE OF THE SECRETION OF PELTATE GLANDULAR HAIRS IN MENTHA HAPLOCALYX BRIG.

电镜观察表明，刚形成的薄荷盾状腺毛的头部细胞，细胞核较大，细胞质浓，其中具一些小液泡，质体和线粒体丰富。分泌前期，质体和线粒体数量增加，体积扩大，质体内出现黑色嗜锇物质。以后，嗜锇物质从质体转移到细胞质中，通过小液泡加工形成的灰色小滴形式进入液泡内，并在液泡内积累直至充满整个液泡。液泡中的灰色嗜锇物质与分泌到角质层下间隙内的分泌物的电子致密度一致，从而认为质体可能是挥发油的最初合成场所。以后，角质层下形成间隙，液泡内的分泌物通过细胞壁分泌到角质层下间隙内，并在此积聚，这些分泌物可能通过角质层破损分泌出去。

t was proved by electron microscopic observation that head cells of peltate glandular hairs in early stages contained a large nucleus and dense cytoplasm with some little vacuoles,numerous plastids and mitochondria.In presecretory stages,the number and volume of plastids and mitochondria increased.The dark osmiophilic material appeared in the plastid.Afterwards,the dark osmiophilic material was transferred from the plastid into the cytoplasm and then into the small vacuoles.The small pale droplets were therefore produced from the small vacuoles.The small pale droplets entered the large vacuoles and accumulated in them until the vacuoles were filled with the droplets.The pale osmiophilic material in the vacuole had the same degree of electron density as the secreted material in the subcuticular space.Therefore it was supposed that the plastid was the primary site where the essential oil was synthesized.Lately,the subcuticular space began to form.The secretory material in the large vacuoles was secreted into the subcuticular space via the cell wall and accumulated in it.Finally,the secretory material might be secreted into the outside by splitting the cuticle.