氧化胁迫对毛白杨叶肉细胞结构和生理功能的影响

Effects of oxidative stress on physiological-biochemical characteristics and mesophyll cell structure of Populus tomentosa Carr.

为了研究氧化胁迫条件下,毛白杨植株细胞结构和生理生化的变化特征,从而为木本植物应对氧化胁迫的研究提供实验依据。本研究以毛白杨组培植株为实验材料,利用过氧化氢溶液浸泡处理离体叶片进行氧化胁迫,测量氧化胁迫前后各项生理指标的变化并观察细胞结构形态的变化。结果表明氧化胁迫后,毛白杨植株内过氧化氢含量明显升高;伴随着NADP^+/NADPH比值的显著升高,抗坏血酸的含量明显下降;同时丙二醛含量明显升高;ADP/ATP比值明显下降;蛋白羰基化程度随过氧化氢含量的升高而增强;叶肉细胞及叶绿体结构发生改变,叶绿体双层膜结构不清晰,类囊体片层结构解体。结论:毛白杨受到氧化胁迫后体内活性氧含量迅速升高,造成膜脂、蛋白质及细胞结构受到不同程度的氧化损伤。

The subcellular structure and physiological-biochemical parameters would change in response to oxidative stress in plant.In order to understand the effects of oxidative stress on physiological-biochemical characteristics and chloroplast structure of Populus tomentosa Carr.,a series of experiments were conducted by using wild type poplar as experimental material which was treated with hydrogen peroxide solution. The results show that the hydrogen peroxide( H_2O_2) and malondialdehyde( MDA) contents in poplar leaves are significantly increased after oxidative stress treatment. Ascorbic acid( As A) content is significantly increased while NADP^+/NADPH ratio is decreased. The content of malondialdehyde and ADP/ATP ratio are significantly decreased. The degree of protein carbonylation is increased with increasing the levels of oxidative stress. The structure of mesophyll cells and chloroplasts are changed. The structure of chloroplast bilayer membrane is unclear and the thylakoid lamellar structure is disorganized. In conclusion,under the oxidative stress,the content of reactive oxygen species( ROS) in plants increases rapidly,and the membrane lipid,protein and cell structure are oxidative damaged.