【摘要】 为探讨短期Cd胁迫对水稻各部位营养元素(Zn、Mg、Cu)、叶绿素以及抗氧化酶活性的影响,从而为控制稻米Cd含量提供理论依据,本研究采用水培试验,探讨了在不同Cd浓度(0、1.25、2.5、5μmol/L)和不同处理时间(0、6、12、24、36、48、72 h)下水稻各部位Cd含量及其吸收速率,以及短期(72 h)Cd胁迫对水稻各部位营养元素、叶绿素以及抗氧化酶活性的影响。结果表明:幼苗期水稻根系Cd含量远远大于茎和叶,各部位对Cd的吸收速率均随着处理时间的增加而下降。Cd由根部向地上部分的转运呈现"低促高抑"的现象,处理72 h后低浓度(1.25μmol/L)胁迫下Cd的转移系数是高浓度(5μmol/L)的2.05倍。在5μmol/L Cd胁迫72 h后水稻叶中叶绿素a和叶绿素b的含量分别下降23.5%、33.3%,CAT和ApX活性分别上升19.11%、28.07%。说明Cd胁迫会抑制水稻对营养元素Zn、Mg、Cu的吸收,抑制叶绿素的合成,引起CAT和ApX活性升高。更多还原

【Abstract】 The experiment aims to investigate the effects of short-term Cd stress on nutrient elements(Zn, Mg,Cu), chlorophyll and antioxidant enzyme activities in various parts of rice, so as to provide a theoretical basis for controlling Cd content in rice.In this study, hydroponic experiments were conducted to investigate the dynamic uptake and transport of Cd by rice and the effects of short-term(72 h) Cd stress on nutrient elements, chlorophyll and antioxidant enzyme activities in different parts of rice under different Cd concentrations(0,1.25,2.5,5 μmol/L)and different treatment times(0, 6, 12, 24, 36, 48, 72 h). The results showed that the Cd concentration in rice roots at seedling stage was much higher than that in stems or leaves. The uptake rate of Cd by roots, stems and leaves decreased with the increase of treatment time, and there was significant difference among treatments. The transport of Cd from the root to the aboveground part showed a phenomenon of "low promotion and high inhibition". After 72 hours of treatment, the transfer coefficient of Cd under low concentration(1.25 μmol/L) was 2.05 times higher than that of high concentration(5 μmol/L). At the treatment concentration of 5 μmol/L, the contents of chlorophyll a and chlorophyll b in leaves decreased by 23.5% and 33.3%, respectively, and the activities of CAT and APX increased by 19.11% and 28.07%, respectively,indicating that Cd stress inhibited the uptake of nutrients(Zn, Mg, Cu) in rice,and the synthesis of chlorophyll, which increased the activity of CAT and APX.更多还原