不同供Zn水平下HCO_3^-对小麦幼苗生长和活性氧代谢的影响

Effect of HCO_3^- on growth of wheat seedling and metabolism actived oxygen under different supply level of zinc

采用营养液培养法 ,研究了不同 p H条件下高浓度 HCO3- 10 mm ol/ L 在缺 Zn和正常供 Zn时对小麦幼苗生长 ,尤其是对活性氧自由基代谢的影响 .结果表明 ,在酸性或碱性营养液中 ,HCO3- 在缺 Zn时均显著降低小麦根系生长量 ,正常供 Zn时 HCO3-对后者的影响则不明显 .缺 Zn条件下 ,HCO3-在 p H为 6的营养液中使小麦根系和叶片中活性氧产生速率分别上升 9.9%和 3.9% ,在 p H为 8的营养液中分别上升 10 .9%和 5 .7% ;正常供 Zn时HCO3- 虽使根系和叶片中活性氧产生速率增加 ,但幅度有所降低 .缺 Zn时 HCO3- 大幅度降低小麦根系中 POD、CAT、SOD3种保护酶的活性 ,而正常供 Zn在一定程度上则能缓解 HCO3- 对小麦根系组织中膜脂的过氧化作用 .正常供 Zn与缺 Zn相比 。

Solution culture experiment with winter wheat seedlings were conducted to study the effect of high HCO_3^- concentration (10 mmol/L) on biomass and metabolism of active oxygen at two pH under different condition of Zn supply. In acid or alkaline solutions, the effects of HCO_3^- on biomass were not obvious at Zn sufficiency. At Zn deficiency, HCO_3^- increased the production rate of active oxygen by 9.9% and 3.9% in root and leaves at pH 6, respectively; and 10.9% and 5.7% at pH 8, respectively. Under normal supply of Zn, although HCO_3^- also increased the production rate of active oxygen in wheat root and leaf, the extent decreased. At Zn deficiency, HCO_3^- decreased the activity of three protective enzymes in roots to large extent, viz. peroxidase (POD), catalase (CAT) and superoxide dismutatase (SOD), however, sufficient Zn supply could mitigate proxidation of HCO_3^- to membrane lipid in root tissues of wheat. Comparing with normal Zn supply and Zn deficiency, the latter increased significantly the autoxidation rate of wheat roots and leaves.