光照强度对烤烟漂浮育苗成苗素质的影响

Effects of Light Intensity on Quality of Tobacco Seedlings in Floating System

以烤烟幼苗为试验材料,采用白纱布遮光方法,设置了自然光、透光68.2%、透光35.4%和透光16.7%4个光照强度处理,研究了光照强度对漂浮育苗成苗素质的影响。结果表明:随着相对光照强度的减弱,烟苗高度增加,茎围、干鲜比、叶片厚度和比叶重等均呈现降低的趋势,烟苗物质积累减少,光强对烟苗叶数的影响不大;遮光条件下生长的烟苗根系不发达,根冠比和根重比减小,根系活力下降;光照强度会影响烟苗的含水率,遮光条件下的烟苗自由水含量增加,束缚水含量降低,适宜光照条件下生长的烟苗则保水能力较强,遮光程度越大保水力越低;随着光照强度的减弱,烟苗叶绿素含量增加,Chla/Chlb比值减小;遮光条件下烟苗的硝酸还原酶活性升高,转化酶活性降低,表明烟苗体内的氮代谢强于碳代谢,抗逆性降低;随着光强的减弱烟苗总氮和蛋白质含量增加,总糖和烟碱含量降低。总之,随着育苗环境的光照强度降低成苗素质下降。

The effects of light intensity on agronomic characteristics of tobacco seedlings were studied under shield of white gauze. The results showed that with the decrease of light intensity, the height of seedlings increased, while the stem circumference, leaf thickness, specific leaf weight, ratio of dry weight to fresh weight and matter accumulation of seedlings reduced; the root systems of seedlings were not well developed, root system vitality lowered and the ratio of root to shoot decreased ; the moisture content of tobacco seedlings was also affected, the free water content was increased and bound water content was decreased by shading; the contents of chlorophyll, total nitrogen and protein and NR activity in tobacco seedlings increased, however, the value of Chla/Chlb, INV activity and contents of total sugar and nicotine decreased. It indicated that the quality of tobacco seedlings declined with the decrease of light intensity under the conditions of 4 light intensities set in this experiment.