水分胁迫对绢毛委陵菜叶绿体超微结构及光合生理因子的影响

Effects of water stress on ultrastructure and photosynthetic physiological factors of Potentilla sericea

以绢毛委陵菜(Potentilla sericea)为材料,通过盆栽试验进行水分胁迫处理并分析幼苗叶片超微结构与净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)、水分利用率(WUE)的关系。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,类囊体片层叠垛整齐。叶绿体嗜锇程度低,嗜锇颗粒少,且体积小;随着自然失水胁迫程度的加强,叶绿体基粒和膜结构断裂,片层排列紊乱,基粒垛叠程度下降;线粒体双膜结构膨大或破裂,内含物流出,嵴减少。光合作用与叶绿体的结构变化相关,随着土壤逐步干旱和叶绿体受损程度的加重,Pn、Tr、WUE有所下降。表明在干旱胁迫下绢毛委陵菜通过改变叶绿体结构和光合生理因子来提高抗旱性。

The leaf ultrastructure of Potentilla sericea under water stress was investigated by transmission electron microscopy.The leaf photosynthetic rate（Pn）,transpiration rate（Tr）,stomata conductance（Gs）,intercellular CO2 concentration and water use efficiency（WUE） were measured by portable photosynthesis system（LI-6400）.The results showed that the leaf ultrastructure was complete under control.Grana lamellaes of chloroplasts were distinct.The number of granas was abundant and the structure was compact.The thylakoids were compact and the grana stacks of thylakoids were regular.The chloroplasts showed lowly osmiophilic.There were few and small osmiophilic grain in the chloroplasts.With the intensive of drought stress,the grana and envelope damaged,the lamella swelled or dissolved and the grana stacks of thylakoids were disorder.Mitochondrial doublemembranes swelled or rived and its inclusion effused.The net photosynthetic rate was closely related to the change in chloroplast structure.The Pn,Tr and WUE of leaf decrease with the declining of soil water content and the damage of chloroplast.