缺铁条件下菜豆植株茎生长素(IAA)与根系Fe^(3+)还原酶活性的关系

Relations between Auxin(IAA) in Shoot Apex and Root Fe^（3+） Reductase Activity of Bean Plants under Iron Starvation

研究了营养液培养条件下，对缺铁菜豆植株进行去顶、涂抹生长素极性运输抑制剂CFM或生长素类物质萘乙酸（NAA）等处理后，其根系还原酶活性的变化情况；同时对缺铁菜豆茎尖可扩散型IAA和茎尖内源生长素进行了测定。结果表明，缺铁菜豆根系Fe3+还原酶活性在处理后第4天有所增加，第6、8天显著提高。缺铁同时去顶或涂抹CFM处理可抑制缺铁菜豆根系Fe3+还原酶活性，而涂抹NAA则可较明显地提高去顶后缺铁菜豆植株根系Fe3+还原酶活性。在缺铁处理后不同天数对缺铁菜豆进行去顶处理，在第7天其根系Fe3+还原酶活性表现为：在0～2日进行处理的植株其根系还原酶活性完全受到抑制；在4～6天处理的植株去顶的抑制作用逐渐减弱。从处理后第1天起，缺铁处理植株茎尖内源生长素含量就显著高于对照，在第2天略有降低，随后在第4、6天又迅速增加。缺铁处理植株茎尖可扩散型IAA含量也经过同样变化过程，只是变化幅度相对较大。因此，从时间进程上看，缺铁菜豆茎尖生长素合成、运输的变化情况及人为进行缺铁菜豆植株生长索运输的改变与其根系Fe3+还原酶活性变化的关系，更加确定地反映出茎尖所合成的生长素可能在调控缺铁菜豆根系Fe3+还原酶活性方面发挥作用。

With nutrient solution culture, the ferric reductase activity in root of iron-deficient bean (Phaseolus vulgaris L. ) plants was investigated. The plants were treated either by decapitation, or smearing with CFM, an inhibitor of auxin polar transport, or with naphthalene acefic acid (NAA), an auxin-like substance. Furthermore, the diffusible IAA and endogeneous auxin in shoot apex of iron-deficient bean plants were determined as well. The results showed that, on the 4th day after treatment, the root ferric reductase activity of irondeficient bean plants without treatment increased slightly, and was enhanced significantly on the 6th and 8th day; and was inhibited by both decapitation and smearing with CFM. The promotion effect of smearing NAA against the surpress effect of decapitation was observed.On the 7th day after iron-deficiency, the root ferric reductase activity of decapitated bean Dlants on different daVs after iron-deficient treatment was inhibited completely by decapitation on the days 0-2, and less inhibition effects were demonstrated gradually by the decapitation on the days 4-6. Since the first day of the iron-deficient treatment, the amount of endogenous IAA in the shoot apex was significantly higher than that of the control plants, decreased slightly on the 2nd day, and increased rapidly again on the 4th and 6th day. And the amount of diffusible IAA in shoot apex of iron-deficient plants was varied in the same pattern. Based on these observations, it is suggested that auxin synthesized in shoot apex'play a role in the regulation of the ferric reductase activity in iron-deficient bean plant the roots.