通过比较不同遮阴处理下棱角山矾幼苗生长及光合特性的差异,以探讨不同光强对棱角山矾生长及光合作用的影响及其适应机制.结果表明:棱角山矾幼苗的生物量分配对光强的反应敏感,在强光处理下,比叶面积减小,总叶面积变小;弱光处理下通过增大叶生物量比、叶面积比,支持结构生物量比,提高捕光能力.但L100、L30、L10处理下总生物量的积累显著小于L50处理,L30、L50、L100光强处理下总叶面积显著高于L10光强处理.并且10%和100%光强下棱角山矾叶片的最大净光合速率(Pmax)、光饱和点(LSP)、表观量子效率(AQY)均显著低于30%和50%光强处理;而光补偿点(LCP)则随光强的增大而升高;总叶绿素和类胡萝卜素含量在10%~100%随着光强增大而显著降低(P<0.05).说明棱角山矾幼苗在不同光环境下具有一定适应性,但过强或过弱的光环境均会对棱角山矾的生长产生负面影响,其中50%光强是棱角山矾幼苗生长的最佳光强;棱角山矾为中性树种,苗木适宜生长在荫蔽的环境下.
By measuring the effects of different shading on seedling morphology of Symplocos tetragona,we studied the response and adaptation mechanism of the growth and photosynthetic characteristics of S.tetragona to changes of light intensity in growth environment.The biomass of S.tetragona seedlings was sensitive to light intensity distribution,under light processing,the ratio of leaf area decreased,the total leaf area decreased.Under weak light treatment by increasing the leaf biomass ratio and leaf area ratio,the biomass ratio was support,and the light harvesting capacity was improved.However,total biomass accumulation under L100,L30,and L10 treatments was significantly less than that under LS0 treatment,and total leaf area under L30,L50,L100 light intensity treatments was significantly higher than that under L10.The growth intensity significantly affected photosynthetic physiological parameters and photosynthetic pigment content of S.tetragona.At 10% and 100% light intensity,leaf maximum net photosynthetic rate(Pmax),apparent quantum efficiency (AQY) and light saturation point(LSP) of S.tetragona were significantly lower than the condition of 30% and 50% light intensity,and the light compensation point(LCP) increased with the increase of light intensity.The total chlorophyll and carotenoid in 10% 100% were decreased significantly with the increase of light intensity (P < 0.05).Too strong or too weak light environment has a negative impact on the growth of S.tetragona,of which 50% is the best light intensity for seedling growth of S.tetragona.S.tetragona is a neutral species,whose seedlings is suitable for slightly hidden conditions.