洞庭湖湿地Cd富集植物蒌蒿(Artemisia selengensis)的耐性生理机制研究

采用盆栽植株和外源Cd胁迫的方法,分别对不同生长期蒌蒿植株根、叶组织中的抗氧化酶活性、可溶性蛋白及MDA含量进行测定,以揭示蒌蒿在Cd胁迫下的抗氧化机理和耐受机制。研究结果表明,Cd胁迫对上述生理指标均有显著影响:≤20mg·kg-1的Cd处理可使幼苗期植株器官中的可溶性蛋白含量增加16.5%～19.1%,100mg·kg-1的Cd含量水平则导致其含量减少近30%,可溶性蛋白含量的变化与植株的生物量积累关系密切;3种酶活性在0～10mg·kg-1的Cd处理下未显示出明显变化,幼苗期植株CAT、POD活性在10～80mg·kg-1的Cd胁迫下增加明显,高于此浓度范围则使酶蛋白受到破坏而失活,中等含量水平(≤40mg·kg-1)的Cd处理经过长时间作用可使植株逐渐适应胁迫环境,胁迫强度较大的Cd处理可显著提高SOD酶的活性;Cd胁迫过程中植株MDA积累量不断增加。3种抗氧化酶活性的增强在蒌蒿植株耐受Cd胁迫方面能起到较好的防御作用。

Physiological Mechanism of Cd-tolerance of Artemisia selengensis Grown in Dongting Lake Wetland

Under the Cd stress,a series of parameters of Artemisia Selengensis including activities of antioxidant enzyme,content of soluble protein and malondialdehyde in leaves and roots were determined during different growth periods of Artemisia selengensis,which was in purpose to clarify the mechanisms of Cd stress tolerance.The results showed that all of the above-mentioned indexes were significantly affected by cadmium.After ≤20 mg·kg-1 Cd treatment at seedling stage of Artemisia selengensis,the soluble protein content of organ increased by 16.5%~19.1%,which reduced nearly by 30% after treatment of 100 mg·kg-1 Cd.The content of soluble protein is closely related to the biomass of plants.Activities of SOD,POD and CAT did not give obvious change when the Cd treatment was less than 10 mg·kg-1.A significant increase of CAT and POD was observed at the Cd concentration of 10~80 mg·kg-1.When the concentration of Cd was higher than 80 mg·kg-1,the enzyme protein was damaged to inactivate.The plant could adapt to the stress environment gradually after exposed to 40 mg·kg-1 Cd for a long time.A high level of Cd stress could increase the activity of SOD obviously.The content of MDA increased continuously throughout the whole Cd stress process was damaged to imactivate.The three kinds of antioxidant enzymes play a good roles in defensing Cd stress.