一定强度的UVC辐射对玉米幼苗活性氧成分及抗氧化系统的影响

The effect of UVC radiation on corn seeding active oxygen species and antioxidant enzyme

通过一定强度UVC照射,对玉米幼苗叶片内几种活性氧成分及几种抗氧化酶的活性变化进行检测,以探究玉米幼苗对UVC照射进行应答的可能机理。实验步骤:玉米幼苗经一定强度的UVC照射5h/d,连续照射5d后,测定超氧阴离子(O_2^-)产生速率及H_2O_2含量,并测定超氧化物歧化酶(SOD)、过氧化氢酶(CAT)及过氧化物酶(POD)的酶活力。结果显示:UVC单独照射时,玉米幼苗叶片内O_2^-产生速率极显著升高(P<0.01),SOD活性、H_2O_2含量及POD活性表现均为极显著降低(P<0.01),CAT活性无明显改变;日光—UVC混合方式照射时,O_2^-产生速率继续升高,SOD活性进一步下降,H_2O_2含量和POD活性则表现为增升(P<0.01),CAT活性极显著降低(P<0.01)。结论:UVC照射对玉米幼苗的损伤主要来自O_2^-,混合光照可加剧这种损伤;混合光照可使H_2O_2含量升高,主要由CAT进行清除;混合光照不是降低UVC对玉米幼苗负面效应的有效措施。

Through a certain intensity UVC irradiation,we detected the change of some reactive oxygen species and antioxidant enzyme activity in corn leaves,then explored the possible mechanism for the corn seeding response to UVC irradiation. Corn seeding was continuously exposed to UVC for 5 days （5hrs/d）,O2- generation rate,H2 O2 content,SOD activity,CAT activity and POD activity were measured as follows：when the corn seeding was irradiated by UVC alone,O2- generation rate promoted significantly（P﹤0. 01）,SOD activity,H2O2 content and POD activity all reduced significantly（P﹤0 . 01 ）,CAT activity had no obvious change;when the corn seeding was exposed to daylight and UVC simultaneously,O2- generation rate kept promoting（P ﹤0. 01）,SOD activity kept reducing（P ﹤0. 01）,H2O2content and POD activity suggested promotion（P﹤0. 01）,CAT activity reduced signifi-cantly（ P﹤0 . 01 ）. The results indicated that the damage in corn seedlings caused by UVC irradiation mainly comes from O2-,mixed light can aggravate the damage. The mixed light can induced H2 O2 con-tent promotion which would be removed by CAT. The mixed light radiation is not an effective measure to reduce the negative effect in corn seeding caused by UVC.