不同降雨条件对不同耐旱型大豆根系的影响

为了明确耐旱型大豆根构型的特异性,田间条件下,以不同耐旱型大豆为研究对象,探讨不同降雨条件对大豆根系特性的影响。结果表明:干旱胁迫降低了各时期大豆植株的根和地上部生物量;同一地点,R2和R4期取样,辽豆14的根和地上部生物量高于辽豆21。随着生育进程的推进,根冠比值逐渐增大;一般而言,V4~R4期,干旱胁迫提高了植株的根冠比。苗期干旱胁迫显著提高了大豆根长,但结荚期和鼓粒期干旱胁迫均降低了大豆根长、根表面积。大豆根长占比以细根为主,平均根直径≤2.5 mm的根长比例均在90%以上。根表面积占比也主要以细根为主,但大豆根体积分配比例较高的却主要是根系直径2.5 mm的粗根。研究结果进一步丰富了耐旱基因型大豆根器官应答干旱胁迫的理论知识,对大豆抗旱生产栽培具有重要的理论价值和实践意义。

Effect of Different Rainfall Conditions on Root System of Different Drought Resistance Soybean

In order to determine the root configuration specificity of the drought durable soybean,field experiments were conducted to investigate the effects of different rainfall conditions on the root characteristics in soybean using different soybean cultivars.The results showed that drought stress reduced the root and shoot biomass at different growth periods in soybean.The root and aboveground biomass of Liaodou 14 were higher than that of Liaodou 21 at R2 and R4 stages in the same location.The ratio of root to shoot increased gradually with the growth of soybean.Generally,drought stress increased the root-to-shoot ratio at V4,R2 and R4 phases.Drought stress significantly increased soybean root length at seedling stage but significantly reduced root length and root surface area at podding stage.Root length ratio was primarily dominated by fine root (root diameter ≤ 2.5 mm),accounting for above 90％ in each period.Soybean root surface area ratio was also dominated by fine roots,however,the higher proportion of root volume was mainly with thick roots which average root diameter was more than 2.5 mm.