美人蕉(Canna indica Linn)镉胁迫的抗氧化机理

Stress responses and resistance mechanism of Canna indica Linn to cadmium

采用水培的方式,探讨了不同Cd2+水平(0、1、2.5、7.5、15 mg.L-1)对美人蕉生物量、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性以及丙二醛(MDA)、谷胱甘肽(GSH)、植物螯合肽(PCs)、酸溶性SH、Cd含量的影响。结果表明,1 mg.L-1的Cd显著提高了美人蕉的生物量(p<0.05),促进了美人蕉的生长。随着Cd2+浓度的提高,SOD、POD、CAT活性以及MDA含量显著增加(p<0.05),表明美人蕉受到了活性氧物质的胁迫。美人蕉中GSH、PCs、SH含量也随Cd2+含量的增加而增加,表明Cd胁迫诱导了PCs的产生,有利于降低Cd对植物体本身的毒害,且根系中的含量均高于叶片。美人蕉中Cd含量随着Cd浓度的增加而显著增加,在15 mg.L-1处理时,地上部Cd含量达到555.4 mg.kg-1,表明美人蕉对Cd有较强的富集能力。

A solution cuhure experiment has been carried out to study the effects of different cadmium levels （0- 15 mg·L^-1） on the biomass, superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT） and malondialdehyde （MDA）, glutathione（ GSH）, PCs（phytochelatins） and total acid soluble SH in Canna indica Linn. The results show that 1 mg·L^-1 Cd in the solution significantly increases the biomass of Canna indica Linn （p 〈 0.05 ）. The activity of SOD, POD, and CAT was increased. The increase of Cd^2＋ enhances the SOD, POD, CAT activity and the MDA accumulation （p 〈0.05）, which indicates that Canna indica Linn has been stressed by Cd. Under this condition, the GSH,PCs,SH in Canna indica Linn increase as well. This means Cd stress induces the production of PCs which helps to decrease its harm to the plant. The roots have more PCs than the leaves. The higher the Cd concentration of the solution used in the experiment the more Cd in the tissues of Canna indica Linn. At the level of 15 mg·L^-1 Cd of the solution, the concentration of Cd in the shoots reaches 555.4 mg·kg^-1, which proves the ample accumulation capacity of Canna indica Linn, and the Canna indica Linn was a potential species for phytoremediation of water polluted by moderate concentration of Cd.