Morphological and Physiological Responses of Acer mono and Quercus liaotungensis Seedlings to a Forest Light Gradient

以萌发后2周的色木槭和辽东栎2种幼苗为试验材料,在森林光环境下根据实际测量值设置4个相对透光率水平：100%,51%,22%和12.8%,观测1个生长季后2种幼苗的存活率、光合能力、光合色素含量、高生长、根系形态以及生物量积累和分配等指标,从而了解2种幼苗在第1个生长季中的存活、生长表现及对不同光环境响应的差异。结果表明：萌发后,色木槭和辽东栎幼苗的整体存活情况相近,但色木槭的最大光合效率、光饱和点及光合色素含量低于辽东栎,苗高、总根长、侧根长和根表面积以及各器官生物量积累等绝对生长量高于辽东栎,且将生物量更多地分配到叶,与之相比,辽东栎幼苗的根生物量分配比重较大;遮荫处理后,在22%和12.8%的相对透光率下,色木槭的存活率下降,辽东栎的存活率增加,且在12.8%的相对透光率下2种幼苗的存活率无显著差异;遮荫处理导致色木槭幼苗的光补偿点和暗呼吸速率显著下降,叶绿素含量增加,光合生理响应大于辽东栎,根系形态响应以及生物量积累和分配的变化响应显著,但小于辽东栎。 To investigate the acclimation of Mono Maple（ Acer mono） and East-liaoning Oak（ Quercus liaotungensis）seedlings under the forest light gradient and the relationship of the acclimation to seedling banks in the oak forests,twoweek-old seedlings of these two species were assigned to four various radiance levels： 100%,51%,22%,and 12. 8% of natural light in the forest environment. We measured their survival,photosynthesis,photosynthetic pigment content,growth,root morphology and biomass accumulation and allocation after one growing season to provide evidences for dynamics of understory