HCO_3^-对不同基因型水稻根生长及养分吸收分配的影响

Effect of HCO_3^- on root growth and nutrient absorption of different rice genotypes.

采用营养液培养法 ,研究了缺Zn敏感 (IR2 6)和耐性水稻品种 (IR8192 31 2 )根生长和养分吸收受HCO-3影响的差异 .结果表明 ,HCO-3( 2 0mmol·L-1)严重抑制敏感品种根系生长 ,特别是在低Zn或缺Zn条件下 ,而对耐性品种影响很小 ,在低Zn水平下 ,对根系生长甚至有轻微的促进作用 .HCO-3不仅抑制敏感品种对Zn的吸收和分配 ,而且也抑制对Cu、Mn和Fe的吸收 ,表明HCO-3对Zn的吸收无专性抑制作用 ,HCO-3抑制敏感品种根系生长可能是其诱发缺Zn的最初作用 .HCO-3处理下 ,耐性品种上位叶和下位叶Zn浓度以及比率高于敏感品种 ,表明耐性品种将Zn从下位叶向上位叶转运的效率高 ,Zn在植物体内的转运能力可能是耐性品种适应石灰性土壤缺Zn的主要机制之一 .

Solution culture experiments with Zn-inefficient cultivar (IR26) and the Zn-efficient cultivar (IR8192-31-2) were conducted to study the effect of HCO - 3 on the root growth and nutrient absorption of different rice cultivars.The results showed that HCO - 3 strongly inhibited the root growth of Zn-inefficient cultivar especially at low Zn concentration.In contrast,that of Zn-efficienct cultivar was slightly stimulated by HCO - 3 at low Zn concentration.HCO - 3 not only inhibited Zn absorption of Zn-inefficient cultivar,but also inhibited its absorption of Fe,Mn,Cu,implying that there was no specific inhibition of HCO - 3 on Zn absorption.These results demonstrated that the inhibition of root growth by HCO - 3 was likely to be the initial action of HCO - 3 in inducing Zn deficiency in lowland rice.With treatment of bicarbonate,Zn concentrations in upper and lower leaves of the Zn-efficient cultivar and their ratios were higher than those of the Zn-inefficient cultivar.The results showed that the Zn-efficient cultivar could transport more zinc from lower leaves to upper leaves,which might be one of mechanisms that the Zn-efficient cultivar adapted to zinc deficiency in calcareous soil.