施用甲醇刺激矮牵牛的生长效应与其代谢关系初探

大量研究表明施用甲醇能够促进多种植物的生长,在甲醇刺激植物生长的机理中,支持碳源假说的证据最多。该研究通过考察矮牵牛甲醇代谢与甲醇刺激其生长的相关性,对碳源假说进行验证。结果表明:(1)在MS固体培养基上添加2和6mmol/L CH3OH均可促进矮牵牛的生长和叶绿素含量增加,但2mmol/L CH3OH(低浓度)效果好于6mmol/L(高浓度),而且添加6mmol/L CH3OH会诱发较强的氧化胁迫。(2)进一步用13 C-NMR分析矮牵牛对不同浓度13 CH3OH的代谢作用发现,6mmol/L 13 CH3OH处理矮牵牛中U-13 C]Fruc和U-13 C]Gluc的生成量显著大于2mmol/L 13 CH3OH处理,即来自甲醇的碳源在代谢过程中虽被卡尔文循环同化为糖类物质,但这部分碳源对甲醇刺激矮牵牛的生长贡献不大。这些证据表明CH3OH代谢与其刺激矮牵牛生长的效果没有关联性,该实验结果不支持碳源假说。

Preliminary Study on the Association between the Growth Promotion and Methanol Metabolism in Petunia Plants

Many studies have shown that methanol(CH₃OH) application can promote growth of various plants.Among the mechanisms of CH₃OH stimulating plant growth,the carbon source hypothesis obtained the most supporting evidence.We attempted to verify the carbon source hypothesis by study the association between the effects on stimulating growth and CH₃OH metabolism in Petunia hybrida.The results showed that:(1)The addition of 2 and 6 mmol/L CH₃OH to MS agar medium all promoted the growth of P.hybrida,but the effect of the former (low concentration) was better than that of the latter (high concentration),and the latter induced stronger oxidative stress.(2)The analysis on ¹³CH₃OH metabolism in P.hybrida under different concentrations by ¹³C-NMR demonstrated that the amount of U-¹³C]Fruc and U-¹³C]Gluc produced from 6 mmol/L ¹³CH₃OH treatment was significantly greater than those from 2 mmol/L ¹³CH₃OH,which results indicated that the carbon source from methanol was assimilated to form carbohydrates through the Calvin cycle.However,this part of carbon source might have little contribution to stimulating growth of P.hybrida.These evidences suggested that there is not association between the effects on stimulating growth and methanol metabolism in P.hybrida,and this experiment do not support the carbon source hypothesis.