外源多胺促进的霍山石斛类原球茎芽发生与H2O2代谢的关系

摘要

[目的]研究外源多胺促进霍山石斛类原球茎芽的发生与过氧化氢(H2O2)代谢酶活性的关系.[方法]主要测定了外源多胺处理后H2O2的动态变化和代谢酶的活性.[结果]外源多胺在有效促进芽发生的同时也能显著提高培养物中H2O2的含量,2.0 mmol/L亚精胺(Spd)或腐胺(Put)处理5d的培养物中H2O2含量分别比对照组高175.6％和180.6％,添加H2O2淬灭剂二甲基硫脲(DMTU)可抑制类原球茎芽的发生,补充Spd或Put可部分解除DMTU的抑制作用.在外源多胺处理前期和中期,虽然超氧化物歧化酶(SOD)和过氧化物酶(POD)活性无明显改变,但合成H2O2的多胺氧化酶(PAO)活性和分解H2O2的抗坏血酸过氧化物酶(APX)与过氧化氢酶(CAT)活性明显增加.[结论]外源多胺作用的霍山石斛类原球茎芽的发生与H2O2积累和分解代谢有关.%[Objective] The research aimed to study the relationship between enhanced conversion of protocorm-like bodies (PLBs) of Dendrobium huoshanense to shoots by exogenous polyamines (PAs) and H2O2-metabolizing enzyme activities.[Method] We mainly measured the dynamic changes of H2O2 and the activities of metabolizing enzyme after exogenous polyamines treatment.[Result] Exogenous addition of PAs not only promoted the conversion frequency of PLBs to shoots but also elevated the levels of H2O2,compared with the control,the H2O2 levels in PAs groups increased by 175.6％ (Spd) and 180.6％ (Put) on the 5th day after being treated using 2.0 mmol/L Spd or Put for 5 days.Dimethylthiourea (DMTU),the scavenger of H2O2,inhibited conversion of PLBs to shoots and the effect could be offset partly by exogenous PAs.Although the activities of superoxide dismutase (SOD) and peroxidase (POD) did not change significantly in the early and middle stages of exogenous polyamine treatment,the activity of polyamine oxidase (PAO) for synthesizing H2O2,ascorbate peroxidase (APX) for dissolving H2O2 and catalase (CAT) were significantly increased.[Conclusion]The occurrence of protocorm buds of Dendrobium huoshanense with the action of exogenous polyamines is related to the accumulation and catabolism of H2O2.