镉胁迫对长春花质膜过氧化、ATP酶及5′-核苷酸酶活性的影响

Effects of Cadmium on Lipid Peroxidation, ATPase and 5′-AMPase Activity of Cytomembrane in Catharanthus roseus Tissues

长春花(Catharanthus roseus)是我国广泛栽培兼具园林绿化和抗癌药源等重要价值的多年生草本花卉植物。为了解镉胁迫下长春花植物体内活性氧清除及其质膜ATP相关酶调控的机理,采用盆栽试验研究了不同镉浓度(0、5、10、25、50、100 mg.kg-1)处理下长春花质膜过氧化、ATP酶及镉富集特性的影响。结果表明:中、低浓度Cd(≤10 mg.kg-1)胁迫下,长春花的丙二醛(MDA)和H2O2含量、超氧阴离子自由基(O2-.)产生速率及抗氧化酶活性与对照没有显著差异。高浓度Cd(≥25 mg.kg-1)胁迫下,地上部MDA、H2O2含量和O2-.产生速率较对照显著升高,且地下部高于地上部;高浓度Cd处理使地上部过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性、还原型谷胱甘肽(GSH)含量及地下部POD、SOD活性显著上升,但地下部CAT活性和GSH含量无明显变化。随着Cd处理浓度升高,地上部H+-ATPase活性逐渐降低,地下部H+-ATPase、地上部和地下部Ca2+-ATPase与5′-AMPase活性均先升后降,在高浓度处理下显著降低。同时,长春花对Cd有较强的富集能力,根系的富集能力高于地上部。

Catharanthus roseus is a perennial herb,which has been widely used in landscaping and in extracting anticancer drug of raw material in China.In order to understand the effects of cadmium on the regulatory mechanism of active oxygen scavenging and cytomembrane ATPase in C.roseus tissues,the lipid peroxidation,ATPase activity of cytomembrane and cadmium accumulation characteristics were mea sured in C.roseus tissues with different treatments including six cadmium concentrations(0,5,10,25,50 mg.kg-1 and 100 mg.kg-1 in soils),employing the method of pot experiment.The results indicated that the malondialdehyde(MDA)content,H 2 O 2 content,superoxide(O 2.)production rate and the activities of antioxidative enzymes in C.roseus tissues were not significantly influenced by lower Cd stress(≤ 10 mg.kg-1),while the accumulation of MDA,H 2 O 2 and O 2.both in shoots and roots of this herb were improved significantly under 25~100 mg.kg-1 cadmium treatment.Moreover,these indices in shoots were higher than those in roots.In addition,high levels of cadmium significantly increased the activities of catalase(CAT),superoxide dismutase(SOD),and peroxidase(POD),and the content of glutathione(GSH) in shoots,as well as the activities of POD and SOD in roots,but did not give strong effects on CAT activity and GSH content in roots.Correspondingly,H +-ATPase activity in the shoot decreased with the increases of cadmium concentrations,while H +-ATPase activity in the root,the activities of Ca 2+-ATPase and 5′-AMPase both in the shoot and root increased with the increase of cadmium concentrations and thereafter decreased.However,the highest cadmium concentration in this experiment inhibited the activities of ATPase and 5′-AMPase in thisplant tissues significantly.In particular,C.roseus has higher capacity in cadmium accumulation,and the capacity of root was higher than that of aboveground tissues.