镧对铅胁迫下小麦幼苗抗氧化酶活性的影响

EFFECT OF LA^(3+) ON THE ACTIVITIES OF ANTIOXIDANT ENZYMES IN WHEAT SEEDLINGS UNDER LEAD STRESS

在铅胁迫的条件下 ,研究了镧对小麦幼苗生长期地上部分及根系超氧化物岐化酶 (SOD)、过氧化氢酶 (CAT)的活性、脂质过氧化产物丙二醛 (MDA)的含量以及对植物生长的影响 .实验在严格控制的人工气候室进行 1 2d .Pb(NO) 3 处理量为 0 ,5 0 ,1 0 0mg·l- 1.在第二天至实验结束的研究结果表明 ,加La组与对照组比较有明显差异 ,根系的SOD和CAT各增加 0 4 5— 1 6 5倍和 32 2— 77 77% ,MDA减少 1 1 0 5—2 7 4 9% .当有铅胁迫时 ,在 0— 5d内 ,与对照组比较 ,镧使小麦幼苗的地上部分及根系的SOD和CAT有少量的但有统计学意义的增加 (p <0 0 5 ) ,MDA含量则减少 .表明La(NO3 ) 3 使抗氧化酶提高 ,增加了小麦抗铅胁迫的能力 ,但是只是在胁迫初期和胁迫不很严重的条件下 ,才具有这一作用 .

The effects of 0.05mg·l -1La(NO 3) 3 on the activities of catalase(CAT),superoxide dismutase(SOD),the level of malondialdehyde(MDA)under lead stress and its effects on plant growth,chlorophyll content in wheat seedlings were studied after administration at 0,50,100 mg·l -1Pb(NO 3) 3 for 12 days.The plants were grown in nutrient solution in strictly controlled climate growth room.A significant effects of La compare with check groups was evident:the activities of SOD and CAT in root were enhanced 0.45-1.65 times and 32.20-77.77% respectively and MDA content was reduced in root 11.05-27.49% from the 2 nd day after treatments till the end of experiment.The activities of SOD,CAT could be increased slightly but significantly(P<0.05)and MDA content be decreased in shoot and root of wheat seedlings by La 3+ under lead stress during 0-5d after treatments compare with check groups.The increased antioxidant enzymes by La(NO 3) 3 enhance the antioxidant potential of the wheat seedlings to reduce lead stress.It can be suggested that La 3+ could remedy lead stress,especially the beginning stress period and the stress was not serius.