自然失水胁迫对绢毛委陵菜叶片超微结构的影响

摘要

利用透射电镜技术对干旱胁迫(自然失水)下及复水后绢毛委陵菜叶片超微结构进行了观察.结果表明:未胁迫的叶肉细胞结构完整.叶绿体基粒片层结构清晰,基粒数目多且排列整齐,基粒类囊体排列致密,美囊体片层叠垛整齐.叶绿体嗜锇程度低,嗜锇颗粒少,并且体积小；随着自然失水胁迫程度的加强,叶绿体基粒和被膜破损,片层膨胀分化或溶解消失,基粒垛叠程度下降；线粒体内外膜膨大或破裂,内含物流出,嵴减少.复水后受轻度和中度胁迫的植株叶内细胞超微结构基本能够恢复正常,受重度胁迫植株的超微结构受到较严重的破坏,无法恢复正常状态,直至死亡.叶绿体对干旱胁迫最敏感,其次是线粒体,可作为委陵菜耐旱程度的细胞学指标.%Leaf ultrastructure of Potentilla sericea under drought stress and rewatering conditions was investigated by transmission electron microscopy. Results show that, under natural conditions, the ultrastructure of mesophyll cells is complete, with distinct grana lamellaes of chloroplasts, abundant and regularly arranged grana, compactly arranged thylakoids, as well as regular stacks of thylakoids. Moreover, the chloroplasts show low osmiophilic level, and there are few and small osmiophil-ic grain in the chloroplasts. However, with the strengthening of drought stress, the grana and envelope are damaged, the lamellae swell or dissolve, and the grana stacks of thylakoids decrease. Mitochondria] inner and outer membranes swell or rive, and its inclusion effuse. The ultrastructure of mesophyll cells under mild and moderate drought conditions could almost return to normal after rewatering, the leaf ultrastructure of the plants under severe drought conditions suffered serious damage, and it would never restore to the normal condition until death. The results above show that chloroplast is most sensitive to drought stress, followed by mitochondria, and they both can be used as cytological indicators of P. Sericea to drought.