生长温度对不同生育期烟草多酚物质代谢的影响

Effects of Different Growth Temperature on Polyphenols Metabolism in Tobacco(Nicotiana tobacum L.) Leaves at Different Growth Stages

为了解不同生长温度对烟叶多酚物质代谢的影响,本研究以云烟87为材料,通过人工气候室模拟云南江川、贵州遵义和河南襄县的气温条件,在烟草移栽-团棵、团棵-现蕾及成熟期进行不同温度处理,研究了不同生长温度对不同时期烟叶多酚类物质含量、代谢途径关键酶活性及其基因表达的影响。结果表明:在不同时期,不同温度下烟草中总酚含量、关键酶活及基因表达之间差异明显;在成熟期以前,烟叶中总酚和木质素含量持续下降,但移栽-团棵期时较低温度(均温16℃)下的总酚含量维持在一个相对较高的水平,而到了团棵-现蕾期,较高温度(均温25℃)更有利于总酚含量的维持;进入成熟期后,烟叶中的总酚含量开始逐渐升高,且较高温度下的总酚积累量最多。对多酚代谢关键酶的检测结果表明,PAL、C4H、4CL、CAD活性与多酚物质含量的变化基本一致,但这些酶基因的表达变化差异较大,与对应酶活性的变化趋势并不完全一致。另外,既参与木质素合成途径又参与多酚氧化分解的PPO、POD活性在烟草的不同生育期内都呈升高趋势,但不同温度处理间差异较大。从总体上来看,河南襄县地区前期稍低后期较高的气温条件更有利于多酚物质的积累,而云南江川地区前期高后期低的气温条件则不利于多酚物质的积累,贵州遵义地区居中。

To investigate the effects of different growth temperature on polyphenols metabolism in tobacco(Nicotiana tobacum L.) leaves at different growth stages, the tobacco cultivar Yunyan 87 was used as experimental material, and the changes of polyphenols content and their metabolism related enzyme activities and gene expression were detected during the transplanting to resettling stage, resettling to squaring stage and mature stage of tobacco plants grown in artificial climate chambers with different growth temperature simulated to the temperatures in Jiangchuan of Yunnan, Zunyi of Guizhou, and Xiangxian of Henan province. The results indicated that in different development stages of the tobacco plants, the changes of polyphenols content and their metabolism related enzyme activities and gene expression exhibited significantly difference under different growth temperatures. during the transplanting to resettling stage, total phenol and lignin content in tobacco leaves decreased obviously, and total phenol content under the low temperature(temperatures averaged 16℃) remain at a relativelyhigh level at this tage. Total phenol content continued to reduce during resettling to squaring stage, but unlike the transplanting to resettling stage, total phenol content under the higher temperature(temperatures averaged 25 ℃)remain at a relatively high level at this stage. After entering mature stage, total phenol content in tobacco leaves began to rise, and the accumulation of total phenol under the high temperature(temperatures averaged 25℃) was the highest by the end of treatment. The activity changes of the key enzymes for polyphenol metabolism including PAL, C4 H, 4CL, CAD were consistent with the change of total phenol and lignin content, but the changes of gene expression of these key enzymes were different significantly and were not consistent with the change of the enzyme activity. In addition, the activities of PPO, POD both involved in lignin synthesis as well as participated in polyphenol oxidative decomposition showed the tendency of increasing at the different growth stages of tobacco,but the difference was significant among different temperature treatment. As a whole, the temperature conditions of Xiangxian of Henan province that slightly lower at earlier stage and higher at later stages is more advantageous to the accumulation of polyphenols, and the temperature conditions of Jiangchuan of Yunnan province that higher at earlier stage and lower at later stage is not conducive to the accumulation of polyphenols.