Effect of CuSO4 Stress on Starch Decomposition in Seed,Anti-Oxidant Properties and Seedling Growth of Wheat(Triticum aestivum L.)
In order to reveal the toxic mechanism of Cu2+stress on wheat seed germination and seedling growth,different doses of CuSO4[0(CK),30,60,and 90 mg·kg-1]were added to 1/100 MS medi-um for soaking and seedling cultivation of wheat by hydroponics,and physiological indicators and growth parameters of wheat seeds,young leaves,and seed roots were measured.The results showed that compared with the CK,the amylase activity,starch granule decomposition rate,total soluble sugar,soluble protein and amino acid content,and antioxidant enzyme activities such as superoxide dismutase(SOD)and catalase(CAT)activity of wheat seeds during germination under CuSO4 stress were significantly decreased(P＜0.05),while the peroxidase(POD)activity was significantly in-creased.After seed germination,the activities of SOD,CAT,and POD in the seed roots increased with the increase of CuSO4 concentration,but the activity of respiratory dehydrogenase,the content of superoxide anion(O2-·),and the fluorescence intensity of H2O2 all significantly decreased.Under CuSO4 stress,Cu2+was mainly accumulated in the seed roots of seedlings,leading to significant inhi-bition of root tip mitosis,and resulting in a significant decrease in plant height,root length,number of seed roots,and plant dry weight.In summary,the toxicity of Cu2+to wheat seedlings exhibits a concentration dependent dose-response relationship.Cu2+inhibits starch degradation during wheat seed germination by reducing amylase activity,causing oxidative damage and ultimately hindering seedling growth.
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