缺铁敏感度不同的大豆品种对缺铁的适应机制

Genotypic Difference in Responses to Iron Deficiency of Glycine max

与供铁处理相比，对缺铁敏感的大豆品种“哈８３”幼苗在缺铁胁迫条件下根际没有酸化现象，根系对Ｆｅ（Ⅲ）的还原能力也没有明显增强。但抗缺铁的大豆品种“８７０１”幼苗根际则严重酸化，根系对Ｆｅ（Ⅲ）的还原能力显著增强；加入能抑制根系Ｈ＋－ＡＴＰ酶活性、减弱根际酸化作用的Ｈ＋－ＡＴＰ酶抑制剂正钒酸钠会降低根系对Ｆｅ（Ⅲ）的还原能力；说明根际酸化与根系还原Ｆｅ（Ⅲ）能力相互联系，初步证实根细胞原生质膜Ｈ＋－ＡＴＰ酶和缺铁诱导的还原酶相互偶联的假说。

Genotypic differences in iron deficiency responses were studied using two soybean genotypes in nutrient solution under controlled environmental conditions.The results showed that there was no significant difference in pH in the rhizosphere of Fe-inefficient genotype ' HA83' between plus Fe and minus Fe, whereas the difference of Fe-efficient genotype' 8701 'was more than 1. 5 pH units. Similar results were obtained by measuring the reducing capacity of the root, where the Fe-efficient genotype had much higher reducing capacity in roots than the inefficient genotype. The addition of H+-ATPase inhibitior vanadate (Na3VO4 )to Fe-deficient plants depressed simultaneously the proton release of roots and the reducing capacity. This result supports the hypothesis about the cooperative functioning system between proton pump and Fe3+ reductase on the plasma membrane of Fe-deficient root cells.