不同光温条件对翠碧一号烤烟碳氮代谢的影响

Effects of Different Light and Temperature Conditions on Carbon and Nitrogen Metabolism of CB-1 Flue-cured Tobacco

为探究烤烟生长后期对光温交互胁迫的响应规律,尤其是应对高温强光等逆境条件时烤烟碳氮的代谢变化,以翠碧一号为供试品种,分别设置25.0℃遮光、25.0℃强光、35.0℃遮光和35.0℃强光等4种不同光温条件处理以探究其对烟株碳氮代谢的影响(光照强度均为1600μmol/m^(2)·s)。结果表明:高温强光处理下,烟株叶片光合色素(Chla、Chlb、Chl和Chlx.c)含量极显著降低,表明烟株光合作用过程受到抑制;蔗糖合成酶(SS)活性显著下降,蔗糖、还原糖、果糖、可溶性糖含量均高于其余3个处理,表明高温强光处理下,SS催化蔗糖合成与分解的反应过程向合成蔗糖方向进行,烟株糖类物质积累增加;高温强光处理下,硝酸还原酶(NR)活性低于25.0℃强光处理,与其余两组处理差别不大,谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)活性极显著高于其它处理,与此同时大多数游离氨基酸含量显著高于其他3个处理,表明高温强光环境显著提高烟株氮代谢能力,含氮物质合成增多,不利于烟叶的品质形成。

In order to investigate the effects of light-temperature interaction stress on flue-cured tobacco at mature stage,especially the changes in carbon-nitrogen metabolism of flue-cured tobacco under high temperature and strong light,CB-1(Nicotiana tabacum L.)was used as the test variety.Four treatments were set,including light shading at 25℃,strong light at 25.0℃,shading at 35.0℃and strong light at 35.0℃.All the light intensity was 1600μmol/(m^(2)·s).The results showed that the contents of photosynthetic pigments(Chla,Chlb,Chl and Chlx.c)in tobacco leaves were extremely significantly reduced under high temperature and strong light,indicating that the photosynthesis process of tobacco plants was inhibited.The activity of sucrose synthase(SS)decreased significantly,and the contents of sucrose,reducing sugar,fructose,and soluble sugar were higher than those of the other three treatments,revealing that under high temperature and strong light,the reaction process of SS catalyzed the synthesis and decomposition of sucrose proceeds towards the direction of sucrose synthesis,and the accumulation of sugars in tobacco plants increased.Under the condition,the nitrate reductase(NR)activity was lower than strong light at 25.0℃and was not much different from the other two treatments.The glutamine synthetase(GS)and glutamate synthase(GOGAT)activities were extremely significantly higher than the others.At the same time,the content of most free amino acids was significantly higher than the other three treatments,indicating that the high temperature and strong light environment significantly improved the nitrogen metabolism of tobacco plants,and the synthesis of nitrogenous substances increased,which was not conducive to the quality of tobacco leaves.