在铝胁迫下离子通道抑制剂和钙螯合剂对黑麦根系分泌有机酸的影响

Effects of ion channel inhibitors and Ca^(2+) chelator on aluminum-induced secretion of organic acids from rye roots

以药理学的方法研究了铝对根系分泌有机酸的诱导作用及钙离子的调控作用。50μm o l/L A l处理24 h后的黑麦根系分泌物的高效液相色谱(HPLC)分析结果表明,铝诱导黑麦根系分泌柠檬酸(C it)与苹果酸(M a l)。在铝溶液中加入阴离子通道抑制剂尼氟灭酸(NA,1~2μm o l/L)、苯甲酰甲醛(PG,10μm o l/L),有机酸的分泌受到极显著的抑制。C a2+通道抑制剂L a(NO3)3(25μm o l/L)、异搏定(VP,25、50、100μm o l/L)显著或者极显著抑制铝诱导的有机酸分泌,而且在50μm o l/L A l溶液中加入的C a2+专一性螯合剂乙二醇-双-(2-氨基乙基)四乙酸(EGTA,250、500μm o l/L)能显著抑制柠檬酸的分泌。这些结果表明,阴离子通道是铝胁迫下黑麦根系分泌有机酸的重要通道,C a2+可能介导此分泌过程。

Pharmacological methods were used to investigate Al-induced secretion of organic acids from roots and the involvement of Ca^2＋ signal in the regulation of secretion. The results revealed by HPLC analysis of root exudates of rye seedlings exposed to 50 μmol/L Al for 24 h showed that Al induced secretion of citrate and malate from rye roots. Application of the anion channel inhibitors 1, 2 μmol/L niflumic acid （NA）, or 10 μmol/L phenlglyoxal （PG） to 50μmol/L A1 solution could suppress secretion siginificanly. M-induced secretion of organic acids was significantly inhibited by Ca^2＋ channel inhibitors such as La （NO3）3 （25μmol/L）, verapamil （25, 50,100μmol /L）. Moreover, addition of special chelator of Ca^2＋ , ethyleneglycol bis （2-aminoethyl ether） （N, N, N＇, N＇ ） tetraacetic acid （EGTA, 250 or 500 μmol/L）, to 50 μmol/L Al solution inhibited significantly secretion of citrate. These results implied that M-induced secretion of organic acids from rye roots may be mediated by anion channels and Ca^2＋ signals may involve in the secretion.