人参光生理研究——Ⅱ.光强对人参叶片生长、叶绿素含量和光合作用特性的影响

本文报道3年来对不同透光率荫棚(光强)下人参叶片生长、叶绿素含量和光合作用特性的测定结果:1.荫棚透光宰低于30％时,处理间叶面积变化不大,超过40％时抑制叶片生长。2.随着光强的增加,叶片叶绿素含量下降。叶绿素a/b比值在5～10％、15～30％和40％以上3种透光率范围的荫棚下呈高、低、高的变化。3.强光下叶片比叶重、净光合作用速率、光补偿点和光饱和点大于弱光下叶片。但当荫棚透光率超过30％时,叶片净光合作用速率不再增加;超过40％时比叶重不再增加。通过对实验结果的分析,作者认为,本实验地区透光率为25～40％的荫棚可能是人参生长的适宜光照条件。

STUDY ON PHOTO-PHYSIOLOGY OF GINSENG I . EFFECT OF LIGHT INTENSITY ON LEAF GROWTH, CHLOROPHYLL CONTENT AND PHOTOSYNTHETIC CHARACTERISTIC

The results of determination, which is made through three years, of leaf growth, chlorophyll content and photo-synthetic characteristic of ginseng leaves grown at different LTR (light transmission rate) shades (light intensity) are reported. 1 .Leaf area grown at shades whose LTR are lower than 30% are nearly the same. Leaf growth is inhibited under the shades whose LTR is higher than 40%. 2. Chlorophyll content decreases with the increase of light intensity.Chlorophyll a/b ratio are lower in the leaves grown under the shades with LTR of 5% and 10%. The leaves grown under shades with LTR of 15%-30% have higher chlorophyll a/b ratio. Chlorophyll a/b ratio decreases in the leaves grown under shades with LTR of 40% and 50%. 3.The leaves grown under high light intensity show higher specific leaf weight (dry weight per unit leaf area), net photosynthetic rate, light compensation point, and light saturation point. Net photosynthetic rate does not increase further in leaves grown under the shades whose LTR is higher than 30%. Specific leaf weight does not increase further in leaves grown under shades whose LTR is higher than 40%. Through analysis on above results, it is believed that shades with LTR of 25%-40% provide good light condition for ginseng growth in our experiment region (Huinan County, Jilin Province).