不同供Zn水平下HCO3-对小麦幼苗生长和活性氧代谢的影响

采用营养液培养法,研究了不同pH条件下高浓度HCO3- (10 mmol/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pH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pH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、SOD 3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,后者显著增加小麦根系和叶片中的自氧化速率.

Effect of HCO3-on growth of wheat seedling and metabolism actived oxygen under different supply level of zinc

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.