镍胁迫对玉米苗根系生长及膜保护系统的影响

目的]研究镍（Ni2＋）胁迫对玉米（Zea mays L.）根系生长及膜保护系统的影响。方法]以玉米为材料,研究了不同浓度Ni2＋胁迫对玉米幼苗根系生长、根系活力及根系中超氧化物歧化酶（SOD）、过氧化物酶（POD）活性和丙二醛（MDA）含量的影响。结果]不同浓度Ni2＋处理对玉米幼苗根系具有低浓度的促进效应和高浓度的抑制效应,且随着浓度的增加抑制效应逐渐增强。根系长度、鲜重、根系活力、SOD活性、POD活性、MDA含量在3个处理阶段（10、30、30 d）变化趋于相同;随着玉米幼苗的生长,各项指标变化更加明显。根系活力在Ni2＋浓度为50 mg/kg（土）时最强,随着Ni2＋浓度的升高而逐渐减弱;根系保护酶系统中SOD和POD活性随着Ni2＋浓度的增加而呈现先升高后下降的变化趋势,在Ni2＋浓度为50 mg/kg（土）时出现峰值;根系细胞内MDA含量在低Ni2＋浓度处理下增幅较小,Ni2＋浓度在100～800 mg/kg（土）时增加显著。结论]Ni2＋浓度低于50 mg/kg（土）时对玉米幼苗期根系的生长有促进作用,而超过该浓度则表现为抑制作用,Ni2＋浓度越高,抑制作用越明显。

Effects of Ni2+ Stress on the Growth and Membrane Protective System of Z.mays L.Seedlings Root

Objective]The research aimed to study the effects of Ni2+ stress on the growth and membrane protective system of Z.mays L.seedling root.Method] The effects of Ni2+ stress on root growth,root activity,superoxide dismutase(SOD) activity,guaiacol peroxidase(POD) activities and the content of malondialdehyde(MDA) of Z.mays L.seedling.Result] The results indicated that Ni2+ had promote effect under low concentrations but inhibitory effect under high concentration for Z.mays L.seedling root,and the inhibitory effect gradually increased with the increasing concentration.The long and fresh weight of root,root activity,SOD and POD activity of root and MDA content of root had the same changes in the three processing stages(10,30,30 d).With Z.mays L.seedlings developing,physiological indices changed significantly.The root activity was the highest at the Ni2+ concentration of 50 mg/kg.Root activity decreased markedly with the Ni2+concentration increased.With the increase of Ni2+ concentration,SOD and POD activities in protective systems increased at first and decreased later.When Z.mays L.seedlings seedling were treated with 50 mg/kg,SOD and POD activities reached the maximum.MDA content increased slightly under the low concentration of Ni2+,while significantly increasing when the Ni2+ concentration was from 100 to 800 mg/kg.Conclusion] 50 mg/kg Ni2+ can promote the seedling root growth of Z.mays L.,but express inhibition effect when Ni2+ concentration over 50 mg/kg.The higher concentration of Ni2+,the more obvious inhibition effect.