低磷土壤条件下菜豆根构型的适应性变化与磷效率

ROOT ARCHITECTURAL RESPONSES TO LOW P AVAILABILITY FROM COMMON BEAN IN THE SOIL IN RELATION TO P EFFICIENCY

利用分层隔网式土壤盆栽系统结合计算机图像分析技术 ,以基根根长、根表面积等在生长介质各层中的相对分布量为指标 ,定量测定菜豆 (PhaseolusvulgarisL .)根构型在低磷胁迫下的适应性变化及其与磷效率的关系。研究结果表明 :在低磷条件下 ,菜豆根部生物量减少 ,根系总长度变短 ,根总表面积减少 ,磷高效基因型G1 9833、G1 9839的基根根长、根表面积降低较少且在介质表层的相对分布量增加 ;而磷低效品种DOR364的根长、根表面积降低较多而在表层的相对分布量减少 ,说明菜豆根构型特征对低磷胁迫具有适应性变化 ,磷高效基因型在低磷条件下能保持一定的根长、根表面积 ,且根系向地性减弱而形成浅根式的根构型 ,使根系内竞争减少 。

Root architecture is closely related to P acquisition efficiency. In the present study, effects of P availability on the root architectural responses of different common bean genotypes were examined. Four common bean ( Phaseolus vulgaris L.) genotypes representing different origins and ecotypic races were compared in a stratified mesh soil pot culture system and root architectural parameters were analyzed with computer image analysis. The results showed that root biomass, total root length and total root surface area were decreased under low P conditions. The P efficient genotypes had a larger, finer and shallower root system than the P inefficient genotypes. The basal roots of G19833, G19839 became shallower while those of DOR364 became deeper under low P conditions. The results from this study suggest that there is great genetic variation in root architectural responses to P availability. The genetic potential of root architectural response provides possibility of selecting this trait for improving P acquisition efficiency in common bean.\;