以铝敏感型黑豆(简称SB)幼苗为实验材料,在水培条件下进行不同浓度过氧化氢(H2O2)和AlCl3处理,考察其生长和相关生理指标变化,探讨H2O2预处理缓解黑豆铝毒害的生理以及分子机理。结果显示:(1)黑豆幼苗根的相对生长量在0.1和1.0μmol.L-1 H2O2处理下始终得到显著促进,并以后者效果更好,而在10.0和100.0μmol.L-1 H2O2处理下先表现促进后受到显著抑制。(2)经过1.0μmol.L-1 H2O2预处理的SB幼苗在不同程度Al 3+胁迫(50~400μmol.L-1)3周后,其叶片和根中总蛋白含量分别显著增加了16.7%~41.2%和10.0%~25.0%,MDA含量减少了近50%;而其同期的SOD和POD活性显著增加。(3)H2O2预处理可诱导SB根和叶中的SOD基因(Mg/Fe-SOD和Mn-SOD)的表达水平明显提高。研究表明,低浓度H2O2能显著促进铝胁迫下铝敏感型黑豆幼苗生长,且主要是通过增加植株抗氧化酶活性和相关基因表达水平来提高其对铝胁迫的抗性。
In this study,the Al-sensitive black soybean(SB) was taken as experimental materials under Al stress to investigate the physiological and molecular mechanisms of the effect of the pretreatment with hydrogen peroxide(H2O2) on alleviating aluminum toxicity.The results show that:(1)The relative root growth of SB is promoted significantly with 0.1 and 1.0 μmol·L-1 H2O2 pretreatment,but promoted first then inhibited with 10.0 and 100.0 μmol·L-1 H2O2 pretreatment.(2)Exposure to different Al concentrations(50~400 μmol·L-1) 3 weeks after pretreatment with 1.0 μmol·L-1 H2O2,the total protein content was increased in both leaves and roots by 16.7%~41.2% and 10.0%~25.0%,respectively;the MDA content was significantly decreased by almost 50%;the activities of SOD and POD improved greatly in SB.(3)RT-PCR analysis showed that pretreatment with H2O2 also increased the expression level of SOD both in SB root and leaf under Al stress.Taken together,pretreatment with H2O2 can promote the growth of SB greatly and enhance the capacity to Al stress by the means of increasing the activities of antioxidant enzymes and their expression levels.