重金属Zn和Cd对翅碱蓬生长及抗氧化酶系统的影响

通过测定翅碱蓬生长和生理指标,研究了不同含量Zn和Cd对翅碱蓬的发芽率、苗高、苗重、体内超氧阴离子自由基(O-2)、过氧化氢(H2O2)的产生及对抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT、过氧化物酶POD)活性的影响,以探讨盐生植物翅碱蓬对重金属胁迫的反应.结果表明,两种重金属均不同程度地加快了超氧阴离子自由基的产生速率;翅碱蓬对Zn胁迫的耐受阈值为100 mg·kg-1,Zn含量低于100 mg·kg-1时,发芽率和苗高、苗重保持良好;含量高于100 mg·kg-1实验组,翅碱蓬生长及体内酶活性机制受到不同程度抑制,SOD 、POD反应迅速,CAT相对缓慢.翅碱蓬对Cd污染抵御能力差,含量高于0.4 mg·kg-l即可造成严重伤害,阻碍翅碱蓬生长,降低抗氧化酶活性.Zn和Cd共同作用(200 mg·kg-1 +0.2 mg·kg-1)时,表现为协同作用,发芽率仅为对照组的50.5％、苗重仅为49.2％,实验50 d后,SOD、CAT均失活,影响极显著.

The effect of Zn and Cd on growth and antioxidant enzymes activity of Suaeda heteroptera Kitagawa

The effects of heavy metals Zn and Cd on germination, height, weight, production of superoxide anion free radical (O₂^-·) and hydrogen peroxide (H₂O₂), and antioxidant enzyme activities of Suaeda heteroptera Kitagawa were studied. Glasswort Suaeda heteroptera Kitagawa was exposed to different Zn and Cd concentrations in order to evaluate the responses of the plant to heavy metal stress. Zn and Cd promoted the production of superoxide anion free radicals. The plant had tolerance threshold of 100 mg·kg^-1 for Zn showing similar germination rate, height and weight in the control group in Zn concentration of under 100 mg·kg^-1. In Zn concentration of over 100 mg·kg^-1, however, the inhibition of growth and the antioxidant enzyme activities were found to some extent in the plant, superoxide dismutase (SOD) and peroxidase (POD) responding rapidly but catalase (CAT) responding slowly. The plant had low resistance to Cd, showing severe damage even at Cd concentration of over 0.4 mg·kg^-1. At this dose of Cd, the growth was hindered and the antioxidant enzymes activity decreased. The synergy effect of Zn and Cd was observed at Zn concentration of 200 mg·kg^-1 and Cd concentration of 0.2 mg·kg^-1 where the germination rate of the experimental plants was found to be only 50.5% of the control group and the plant weight 49.2% of the of the control group. The SOD and CAT were both inactivated at Zn concentration of 200 mg·kg^-1 and Cd concentration of 0.2 mg·kg^-1 in the 50 day experiment. The findings will provide a reference for halophytes toxicology study in contaminated coastal beach.