摘要
根系受渗透胁迫时杨树 (Populus× euramericana cv.‘N30 16’)叶片净光合速率和表观量子效率降低 ,出现光合作用的光抑制 ;O- ·2 产生加快 ,超氧化物歧化酶 (SOD)活性升高 ,H2 O2 生成增加 ;过氧化氢酶和抗坏血酸过氧化物酶活性降低 ,H2 O2 清除减少 ,活性氧代谢平衡受到破坏 ,膜脂过氧化产物丙二醛 (MDA)含量增加。胁迫时用O- ·2 诱导剂百草枯 (PQ)或 SOD抑制剂二乙基二硫代氨基甲酸铜盐 (DDTC)处理使叶片中活性氧和 MDA含量升高 ,光抑制加剧 ;以抗氧化剂抗坏血酸 (As A)处理使胁迫时叶片 O- ·2 生成减少 ,保护酶活性升高 ,H2 O2 和 O- ·2 的水平降低 ,膜脂过氧化受到抑制 ,MDA含量降低 ,同时缓解了光合作用的光抑制。相关分析表明光合作用与活性氧代谢有极显著的关系。推测胁迫时杨树光抑制的发生与活性氧的积累有一定的关系。
The effects of paraquat, diethyldithiocarbamic acid copper salt and ascorbate on photosynthetic photoinhibition were studied in intact leaves of poplar clone seedlings which were suffering root osmotic stress conditions. Photoinhibition was measured through the decrease of apparent quantum yield and photosynthetic rate. Production of H 2O 2 also increased due to the higher O -· 2 generation rate and the activity of superoxide dismutase (SOD) and H 2O 2 scavenging decreased due to the lower activities of catalase (CAT) and ascorbate peroxidase (APX), which disturbed the balance of the reactive oxygen species metabolism. Subsequently, malondialdehyde (MDA), a product of peroxidation of membrane lipids, content also increased. Reactive oxygen species and MDA concentrations increased when treated with paraquat, O -· 2 inducer, and diethyldithiocarbamic acid copper salt (SOD inhibitor) and photoinhibition accelerated. H 2O 2 and MDA content decreased when treated with ascorbate (an antioxidant) due to the decrease in O -· 2 generation rate and the increased activities of protective enzymes. In turn this acted to alleviate photoinhibition. The content of reactive oxygen species and MDA in poplar leaves was correlated negatively with net photosynthetic rate (Pn) and apparent quantum yield (AQY). The activities of CAT and APX were correlated positively with Pn and AQY. This study suggests that photoinhibition of photosynthesis in the leaves of poplar clone seedlings might be intrinsically related to the accumulation of reactive oxygen under root osmotic stress conditions.
出处
《植物生态学报》
CAS
CSCD
北大核心
2001年第4期451-459,共9页
Chinese Journal of Plant Ecology
基金
国家"九.五"科技攻关项目 (96 -0 11-0 1-0 2 )
