研究了林下（L）云锦杜鹃（Rhododendron fortunei）树苗对林窗（H）和林缘（M）不同强度光照的生理响应。夏季将林下发育成熟的云锦杜鹃树苗分别转移到林窗（L-H）和林缘（L-M）后，云锦杜鹃的最大光化学效率和表观量子效率立即降低，随后L-H植株恢复缓慢，而L-M植株快速恢复并接近原来的水平，表明L-H植株发生了严重的光抑制；转移后一个月，与L-H植株相比，L-M具有较高的光合能力，这与两者之间实际量子效率、叶氮含量、比叶重和叶绿素含量等的差异有关；L-M植株还具有较高的对光能的化学利用效率和较低的非光化学淬灭；林下云锦杜鹃对强光的适应状况取决于其所处环境的光照强度，要适应增强的光照并避免严重的光抑制，转移前后光照强度的差异不能过大，否则将导致严重的光能过剩；林下云锦杜鹃适宜的转移生境是林缘。%Experiments were conducted on the physiological response of understory-developed (L)Rhododendron fortunei saplings exposed to higher light (H: canopy gap, M: forest edge) in the summer. The result demonstrated that the maximum photochemical efficiency of PSII (Fv/Fm) and apparent quantum yield (AQY) decreased immediately and was followed by a slow recovery in L-H leaves and a rapid recovery in L-M leaves, indicating that photoinhibition in L-H leaves was greater than that in L-M leaves. Their difference had correlated with real quantum efficiency of PSII (PhiPSII), leaf N content (Narea), leaf mass per unit area (LMA) and chlorophyll content. L-M leaves had greater photo chemical quenching coefficient (qP) and lower non-photo chemical quenching coefficient (qN), compared to L-H leaves. The experiment demonstrated that the physiological acclimation on exposure to higher light depended on the degree of light. In conclusion, forest edge was proved to be optimal for photosynthesis of shade-developed leaves of R. fortuneisaplings.
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