【摘要】 为进一步解析作物对水体中微囊藻毒素（MCs）的适应机制,通过水培试验研究MCs对水稻幼苗营养吸收及质膜H⁺-ATPase基因表达的影响。结果表明:胁迫7 d后,1μg·L^-1MCs组水稻幼苗根系活力增加。10μg·L^-1MCs组水稻幼苗根系活力和质膜H⁺-ATPase活性增加,促进了矿质营养(Mg²⁺、Fe²⁺、Zn²⁺和NO₃^-)的吸收。其中质膜H⁺-ATPase活性上升与OSA1、OSA2、OSA3、OSA4、OSA6、OSA8和OSA9表达上调有关。高浓度MCs(100μg·L^-1和1000μg·L^-1)组水稻幼苗根系活力和质膜H⁺-ATPase活性降低,阻碍了水稻幼苗对矿质营养的吸收,此时质膜H⁺-ATPase的基因表达呈下调趋势,且降低程度随MCs处理浓度增大而增强。恢复7 d后,10μg·L^-1MCs组根系活力、质膜H⁺-ATPase活性和营养元素含量恢复至对照水平。100μg·L^-1MCs组各指标均优于胁迫期,而1000μg·L^-1MCs对营养吸收的抑制未恢复。研究表明,MCs胁迫导致的水稻幼苗中营养元素含量的变化受质膜H⁺-ATPase活性的调控,且调控能力受MCs浓度限制。更多还原

【Abstract】 In order to further analyze the adaptation mechanism of crops to microcystins（MCs）in water, we studied the effects of MCs on nutrient absorption and the expression of the genes encoding plasma membrane H⁺-ATPase in rice seedlings, using a hydroponic experiment. After exposure to MCs for 7 days, the root activity（dehydrogenase activity）of rice seedlings treated with 1 μg·L^-1 MCs increased.The root activity and the activity of plasma membrane H⁺-ATPase of roots of rice seedlings treated with 10 μg·L^-1 MCs increased, promoting the absorption of mineral nutrients(Mg²⁺, Fe²⁺, Zn²⁺and NO₃^-). The increase in plasma membrane H⁺-ATPase activity was related to the up-regulation in expression levels of genes OSA1, OSA2, OSA3, OSA4, OSA6, OSA8 and OSA9. High concentration of MCs(100 μg·L^-1 and 1000 μg·L^-1)reduced the root activity and plasma membrane H⁺-ATPase activity of rice seedlings, inhibiting the absorption of mineral nutrients. The expression levels of genes encoding plasma membrane H⁺-ATPase showed a trend of down-regulation and the degree of reduction of nutrient absorption increased with increasing concentration of MCs. After recovery for 7 days, root activity, plasma membrane H⁺-ATPase activity and mineral nutrient content in rice seedlings treated with 10 μg·L^-1 MCs returned to control levels. All parameters in plants treated with 100 μg·L^-1 MCs recovered compared to those measured during the exposure period. The inhibition of absorption of mineral nutrients caused by 1000 μg·L^-1 MCs did not recover. In conclusion, the changes in nutrient absorption in rice seedlings caused by MCs are regulated by plasma membrane H⁺-ATPase activity, and the effect of regulation is dependent on the concentration of MCs.更多还原