Effect of Cd Stress on Seed Germination and Antioxidant Enzymes of Lettuce

The effects of different Cadmium(Cd)concentration on seed germination,the growth of radicle and plumula,melondialodehyde(MDA)and the activities of antioxidant enzymes were investigated.The results showed germination rate decreased with the increasing of Cd concentration.Germination potential,germination index,vigour index and the length of radicle were promoted at lower Cd concentration and inhibited at higher Cd concentration.Moverover,Cd had more inhibition effects on radicle growth than plumula.The content of MDA and activities of SOD and G-POD in radicle increased significantly with the increasing of Cd concentration,whereas,the activities of APX and CAT decreased markedly.The content of MDA and the activities of SOD,G-POD,APX,CAT did not change significantly except at the higher Cd concentration(100 μmol/L).