多胺诱导大豆子叶节愈伤组织形成丛生芽的机理研究

Study on the Mechanism of Clump Bud Generation Induced by Polyamines in Soybean Cotyledon Node Callus

以栽培大豆幼苗子叶节愈伤组织为材料,研究多胺氧化降解产物H2O2在大豆子叶节愈伤组织丛生芽形成中的作用。结果表明:浓度为0.5 mmol·L-1时3种外源多胺(Put,Spm和Spd)都能显著促进大豆子叶节愈伤组织分化形成丛生芽,其中Spd的作用最显著,Put和Spm作用次之,而亚精胺合酶抑制剂-环己胺(CHA)对大豆子叶节丛生芽的形成有较强的抑制作用。与此对应的是,外源多胺处理促进了子叶节外植体的二胺氧化酶(Cu AO)活性和H2O2含量水平。有趣的是,用多胺氧化酶抑制剂-氨基胍(AG)和H2O2清除剂DMTU分别处理,也可显著抑制多胺对大豆子叶节愈伤组织分化形成丛生芽的促进作用;AG和DMTU在丛生芽分化上的作用,可能与AG处理导致外植体Cu AO活性和H2O2水平的降低,以及与DMTU清除H2O2的作用有关。研究结果暗示多胺降解产物H2O2可能参与多胺对大豆子叶节愈伤组织丛生芽的诱导。

Cotyledon node callus of soybean seedlings was used to study the role of hydrogen peroxide from polyamine degradation in induced generation of clump buds in soybean cotyledon node callus. The results showed that three of the exogenous polyamines significantly enhanced clump buds formation of soybean cotyledon node callus,0. 5 mmol·L- 1Put was more effective than Spm,but less than Spd. Meanwhile cyclohexylamine（ CHA）,an inhibitor of Spd synthase,displayed a strong inhibitory effect on the formation of clump buds. Accordingly,activity of diamine oxidase and levels of hydrogen peroxide in the explants of cotyledon node were greatly increased. Interestingly,polyamine-increased differentiation of clump buds was strongly reduced after the application of diamine oxidase inhibitor-aminoguanidine（ AG） and H2O2scavenger- dimethyl thiourea（ DMTU）,respectively. Probably,the effects of AG and DMTU on clump buds differentiation were associated with decreases in Cu AO activity and the level of H2O2 caused by AG treatments,and H2O2 scavenging by DMTU. These results suggest that hydrogen peroxide from polyamine degradation is potentially involved in inductive formation of clump buds in soybean cotyledon node callus.