Effect Of Indole Acetic Acid On Cadmium Uptake And Physiological And Biochemical Cha Nges Of Different Maize Cultivars

In this paper,three maize varieties(Hua Nuo number 2,Hui Dan number 4,Yao Xi number 1)were used as materials to carry out the indoor hydroponic experiment.Different concentrations of indole acetic acid(IAA)(0 mg/L,5 mg/L,15 mg/L,30mg/L)was sprayed on the leaves and roots of the maizes,respectively under stress of the same concentration of Cd(0.5 mg/L),to comparatively study the effects of the above two treatments on the malondialdehyde(MDA)content and antioxidant system of the peroxidase(POD),superoxide dismutase(SOD)and catalase(CAT)of maize seedlings.The results showed that both treatments reduced the MDA content and decreased the activities of POD,CAT and SOD in the leaves of three maize varieties compared to those under Cd stress alone.This indicated that IAA could alleviate the damage to maize seedlings by Cd stress and affect the activity of antioxidant enzymes by inhibiting the plant tolerance to Cd.Comparing the two different treatments,the root IAA application had more obvious effects on the MDA content and antioxidant system than the leaf IAA spraying.This was because IAA uptake by maize seedlings was mainly in the roots.IAA could initiate complexation and chelation with Cd around the roots of maize seedlings,therefore the root IAA application was more significant and effective than the leaf IAA spraying.