活性铝对小麦根生长及酶活性的影响

利用铝形态分布与环境pH的相关性,通过改变染毒液pH条件,研究了不同浓度活性铝对小麦根生长、蛋白质含量及酸性磷酸酶活性的影响,并探讨了不同形态活性铝植物毒性的差异.本实验染毒液中总铝浓度设置为0(CK)、25(T₁)和75μmol·L^-1(T₂)3组,各组pH分别调至4.0、4.5、5.0和5.5.结果表明,微量Al_a与Al_b对小麦根生长均具有抑制作用.但随染毒液中活性铝组分的改变,小麦根蛋白质含量和酸性磷酸酶活性显现相反变化趋势:T₁和T₂组在pH4.0,活性铝主要成分为Al_a时(Al_a浓度高于活性铝浓度的90%),小麦根细胞蛋白质含量显著下降,酸性磷酸酶活性显著上升;T₁和T₂组在pH5.0,Al_a浓度降低至与Al_b浓度接近,且Al_a和Al_b浓度均低于10μmol·L^-1时,根细胞蛋白质含量显著上升,酸性磷酸酶活性显著下降.

Effects of aluminum speciation on wheat root growth and its enzyme activity

Aluminum speciation is recognized to associate with environmental pH. In this paper, the effects of aluminum speciation (A1a, A1b) on the growth, protein content, acid phosphatase (AP) activity of wheat root were studied by changing the pH of aluminum solutions. Two concentrations of total aluminum, 25 micromol x L(-1) (T1) and 75 micromol x L(-1) (T2), were set up in the test solutions, and four levels of pH, 4.0, 4.5, 5.0 and 5.5, were regulated for each solution. The results indicated that the growth of wheat root in T1 and T2 was strongly inhibited by low doses of Ala and Alb, while the changing trend of protein content and AP activity varied when exposed to different composition of active A1. When the A1a concentration was above 90% of the active Al concentration, the protein content was reduced while the AP activity was enhanced by Al at pH 4.0, but it was reverse at pH 5.0 when the concentration of Ala and Alb was below 10 micromol x L(-1), respectively.