中文摘要：

铝对植物的毒害作用主要表现在抑制根系的生长和发育上。为了考察生长素（IAA）对铝毒的缓解效应，以铝耐受型黑大豆（简称RB）和铝敏感型黑大豆（简称SB）为材料，研究了铝胁迫下外源添加IAA对RB和SB根系生长的影响。结果表明：外源添加IAA可以明显缓解铝胁迫对RB和SB主根生长的抑制作用，并且能显著促进侧根的发育以及生物量的增加。RB在铝胁迫下外源添加不同浓度（0．5，1，25和50μmol·L-1）IAA后，主根长、侧根数目和长度、根冠比和鲜重与仅有铝胁迫处理相比随着IAA浓度的升高而升高。其中，在铝胁迫下外源添加50μmol·L-1IAA对RB的主根长、单位主根上的侧根数、侧根长、根冠比和鲜重促进效果最佳，与仅有铝胁迫处理相比分别增加了26．72％、110．69％、12．89％、58．76％和51．94％。与RB相似，SB在铝胁迫下外源添加不同浓度（0．5，1，25和50μmol·L-1）IAA处理后，其主根长、侧根数和侧根长、根冠比和总鲜重与仅有铝胁迫处理相比也得到有效的增加。在铝处理液中添加25μmol·L-1IAA对sB主根长、单位主根上侧根数目、侧根长、根冠比和鲜重的促进效果最佳，与仅有铝胁迫相比分别增加了41．02％、63．26％、16．01％、45．41％和39．43％。结果说明，外源添加IAA可以有效缓解铝对植物的毒害作用。

英文摘要：

The inhibition of root growth and development is the main toxic performance of aluminum（A1） on plant growth. To gain insight into the alleviative effects of auxin （IAA）on A1 toxicity, the Al-resistant（RB） and Al-sensitive（SB） black soybeans were used as the materials to investigate the effect of exogenous IAA on root growth under A1 stress conditions. The resuhs showed that exogenous application of IAA could not only alleviate the Al-induced inhibition of primary root growth, but also promote the lateral root development and increase the biomass in both RB and SB. After application different concentrations of IAA （ 0.5,1,25 and 50 ~mol-L-~ ）in 50 p~mol＂ L- J A1 treatment solution, primary root length, lateral root number and length,root/shoot ratio and fresh weight of RB were increased in a concentration-dependent manner, compared with A1 treatment. Adding 50 μmol·L-1 IAA in the A1 treatment solution had the best promotion effect on primary root length, lateral root density Adding 50 μmol·L-1IAA in the A1 treatment solution had the best promotion effect on primary root length, lateral root density and length, root/shoot ratio and fresh weight of RB, and increased approximately 26.72%, 110.69%, 12.89 %, 58.76 % and 51.94% ,respectively,compared with A1 treatment. Similarly,exogenous application of 0.5,1,25 and 50 μmol·L-1 IAA in Al treatment solution,primary root length, lateral root density and length, root/shoot ratio and fresh weight of SB were also increased to some extent. Whereas, exogenous applying 25 μmol·L-1 IAA in 50 μmol·L-1 A1 treatment solution had the best promotion effect on SB primary root length,lateral root density and length, root/shoot ratio and fresh weight, and increased approximately 41.02% ,63.26% , 16.01% ,28.87% and 39.43%, respectively, compared with only Al treatment. Results suggested that exogenous applying IAA could efficiently alleviate A1 toxicity to plant.