温度对烟草叶片细胞壁物质含量及组成变化的影响

Effects of temperature on content and composition of cytoderm substances in tobacco leaves

为探究温度影响烟草叶片细胞壁建成的机理和烟叶品质的机制,连续2年设置不同温度(15℃、20℃、25℃、30℃)处理的盆栽试验,研究不同温度对烟草叶片细胞壁物质含量和组成及合成酶基因表达量的影响。结果表明,含碳化合物在烟草叶片生长过程中及温度处理过程中发生了重新分配,随着烟草生长时间的延长,叶片中结构性碳水化合物(纤维素、半纤维素、木质素、果胶)含量整体表现为下降趋势,而非结构性碳水化合物(总糖、淀粉)含量大致表现为上升趋势;随温度升高,烟草叶片60 d时纤维素含量明显升高,而木质素含量及其占细胞壁总物质含量的比例明显降低;温度对半纤维素含量、果胶含量影响不显著。温度对纤维素含量、木质素含量的影响与其合成酶基因表达量的变化有关,温度升高有利于纤维素合成酶基因CESA1的上调表达,温度降低有利于木质素合成酶基因PAL1、4CL2的上调表达;温度变化对半纤维素合成酶、果胶合成酶基因表达的影响较小。

To investigate the mechanisms of temperature in affecting cytoderm formation of tobacco leaf and tobacco leaf quality,pot experiment under different temperature treatments(15℃,20℃,25℃,30℃)was set for two consecutive years to study the effects of different temperatures on the substance contents and composition of cytoderm,as well as expression amount of synthase genes in tobacco leaves.The results showed that,carbon compounds redistributed during the growth process of tobacco leaves and under different temperature treatments.With the extension of growth time,contents of structural carbon compounds(cellulose,hemicellulose,lignin,pectin)in tobacco leaves decreased on the whole,while contents of non-structural carbon compounds(total sugar,starch)increased approximately.The cellulose content of tobacco leaves at 60 d increased obviously,while the contents of lignin and the ratio of lignin contents to the total substance content in the cytoderm reduced significantly with the increase of temperature.The temperature had no significant effect on hemicelluloses and pectin contents.The effect of temperature on the contents of cellulose and lignin was related to the changes in the expression of related synthase genes.Increasing temperature was beneficial to the up-regulation of cellulose synthase gene CESA1,while decreasing temperature was beneficial to the up-regulation of lignin synthase genes PAL1 and 4Cl2.Temperature changes had slight impact on the expression of hemicelluloses and pectin synthase genes.