【作者】 唐新莲； 黎晓峰； 顾明华； 凌桂芝；

【Author】 Tang Xin-lian LI Xiao-feng Gu Min-hua Ling Gui-zhi College of Agriculture,Guangxi University,Nanning 530005 China

【机构】 广西大学农学院；

【摘要】 铝诱导根系分泌有机酸是植物抵御铝毒的重要机制,然而,有机酸分泌的机制尚不清楚.本研究采用药理学的方法和激光共聚焦扫描显微技术探讨了胞内钙离子在铝诱导黑麦根系分泌有机酸的作用.结果表明,铝诱导黑麦根系分泌柠檬酸和苹果酸、增加[Ca²⁺]cyt,200、300 μmol·L^-1AlCl₃处理后黑麦根尖 Ca²⁺的荧光强度增强、波动加剧。然而,铝引起的根尖 Ca²⁺荧光强度的变化因 Ca²⁺通道抑制剂异搏定(VP,100 μmol·L^-1)、胞内 Ca²⁺通道阻断剂辽红(RR,0.5 μmol·L^-1)的处理受干扰后,铝诱导的有机酸分泌受阻。在不加铝处理的条件下,VP、 RR 也有效干扰胞内 Ca²⁺的荧光强度的变化.并且,铝诱导的根尖[Ca²⁺]_cyt的改变及有机酸分泌也受 TFP 处理的干扰和抑制。EGTA 处理使铝诱导的根尖 Ca²⁺荧光信号减弱并出现加大幅度的波动,而0、0.5、1.0 mmol·L^-1 CaCl₂溶液中的 EGTA(0.5 mmol·L^-1)均显著抑制铝诱导的柠檬酸分泌。这些结果说明,根尖[Ca²⁺]_cyt可能是介导铝诱导黑麦根系分泌有机酸的胞内信号因子。更多还原

【Abstract】 It has been proposed that Al-induced secretion of organic acids from roots is a mechanism for plant to resistant Al toxicity,but so far the knowledge about the mechanisms responsible for Al-indueed secretion of organic acids is still very limited.In present study,the effect of intracellular Ca²⁺on Al-in- duced secretion of organic acids from roots of rye was investigated by pharmacological way and technology of confoeal seaning microscopy.The results were shown that,Al not only induced the secretion of both cit- rate and malate,but also elevated the levels of[Ca²⁺]cyt of root apices and enhanced the fluctuation of [Ca²⁺]cyt.However,the inhibition of Al-induced secretion of organic acids was followed by the interrup- tion of Al-indueed alternation in[Ca²⁺]cyt fuloreseence intensity of roots treated with VP(Ca²⁺channel inhibitor,100 μmol·L^-1)or RR(intracellular Ca²⁺blocker,0.5 μmol·L^-1).In the absent of Al³⁺,the change of Ca²⁺fluorescence intensity was also interfered effectively by VP,RR.Moreover,[Ca²⁺]_cyt and the secretion of organic acids were also interfered or inhibited by the treatment with TFP（CaM antago- nist）.Furthermore,the treatment with EGTA(Ca²⁺chelator,0.5 mmol·L^-1)in₀,0.5,1.0 mmol·L^-1 CaCl₂ solutions resulted in a wide fluctuation of[Ca²⁺]cyt and a weak Ca²⁺fluorescence intensity,while the treatment inhibited Al-indueed secretion of citrate.These results suggested that[Ca²⁺]_cyt in tip root might be a signal factor regulating Al-indueed secretion of organic acids from roots in rye,and the anion channel of plasma membrane might be the terminal effeetor in Al-indueed Ca-signal transduction pathway.更多还原