光照强度对成熟期烤烟衰老生理特性的影响

为了解光照强度对烤烟衰老生理特性的影响,探明其在植株衰老过程中的调控作用,以云烟87为材料,设置5个光强梯度:100%自然光(T1)、85%自然光(T2)、76%自然光(T3)、68%自然光(T4)、58%自然光(T5),探讨不同光强下成熟期烤烟叶片中与衰老有关的光合色素、可溶性蛋白、丙二醛含量及SOD、POD、CAT等抗氧化酶活性的变化。结果表明:成熟期烤烟叶绿素a、b含量随光强降低而增加,类胡萝卜素含量及chla/b则随光强减弱而下降;丙二醛含量基本随光强减弱呈降低趋势,成熟中期T2处理丙二醛含量最低;可溶性蛋白含量前期以T2处理最高,其他处理随光强减弱基本呈降低趋势,后期则以T5最高;全光照下抗氧化酶类活性整体较低,适度光照(T2、T3)下抗氧化酶活性较高,其活性随光照减弱而降低。可见,以抚州为代表的南方部分烟区,76%~85%的光照对成熟期烤烟最为适宜,且成熟后期适宜烤烟生长的光照强度较低。

Effects of Light Intensity on Senescence Physiological Characteristics of Flue-cured Tobacco at Mature Stage

In order to study the effect of light intensity on the physiological characteristics of flue cured tobacco and effect of its regulation on the senescence of flue-cured tobacco, this paper carried out experiments by taking flue-cured tobacco Yunyan 87 as material and setting 5 intensity gradient: 100% (T1), 85% (T2), 76% (T3), 68% (T4) and 58% (T5) natural lights, and investigated the effect of light intensity on photosynthetic pigment, soluble protein and MDA content and changes in SOD, pod, cat antioxidant enzyme activities. The results showed that the contents of chlorophyll a and b increased with the decreased of light intensity, the contents of class carrot element and Chla/b decreased with the light intensity decreasing; while the content of malondialdehyde(MDA) decreased with the decreasing of light intensity, and the content of MDA in T2 treatment was the lowest in mature stage; soluble protein content in the early stage in T2 was the highest. The other treatments decreased with the light intensity decreasing, in the latter stage T5 was the highest. Under full light the antioxidase activity was relatively lower as a whole, but under moderate light (T2 and T3) it was higher. Its activity decreased with light intensity reduction. It indicated that in southern tobacco growing areas such as Fuzhou, 76%~85% light intensity is suitable for the flue-cured tobacco In maturing stage, and the suitable light intensity for flue-cured tobacco in late maturing stage was even lower.