摘 要 ：以高山杜鹃‘Furnivall’ s Daughter’ 3年生植株为材料，采用遮阳网遮荫方法设置100%（L1）、53%（L2）、30%（L3）、17%（L4）全光照，研究不同光照对其光合特性及其相关生理特性的影响，探讨高山杜鹃对不同光强的响应及适应机制。结果表明：（1）与全光照条件相比，遮阴处理可有效提高光饱和点（LSP），降低光补偿点（LCP）和呼吸速率（Rd），从而具有较高的净光合速率（Pn）；其中L3处理植株的LCP、Rd最低，而且其LSP和饱和光合速率（Pmax）最高，表明L3光照条件是其最适宜的生长光强。（2）随着光照强度的降低，叶片的叶绿素a呈轻微下降趋势，而叶绿素b、单位面积叶氮含量（LNCa）、光合氮利用效率（PNUE）则呈显著增加趋势，且光照强度对叶绿素b的影响较叶绿素a敏感，从而导致总叶绿素含量显著增加，而叶绿素a/b比值下降。（3）可塑性分析结果表明，高山杜鹃‘Furnivall’s Daughter’ 主要通过Pmax、LSP、LCP、Rd、PNUE和叶绿素含量的改变来适应光环境的变化，而比叶重（LMA）、LNCa、丙二醛（MDA）、超氧化物歧化酶（SOD）在其适应光环境的过程中作用较小。
Abstract:To study the photosynthetic characteristics and physiological characteristics under different light intensities,to know the response of the light intensity and adaptive mechanism of Rhododendron ‘Furnivall’s Daughter’,we potted 3 years old Rhododendron ‘Furnivall’s Daughter’ under four different light intensity levels:100% of full sunlight (L1),53% of full sunlight (L2),30% of full sunlight (L3) and 17% of full sunlight (L4),which were controlled by sunshade screen.The result showed that:(1)Compared with the plant growing in full sunlight,appropriate shade can effectively improve the light saturation point (LSP),decreased the light compensation point (LCP) and respiration rate in the dark (Rd),thus the shaded plants had strongernet photosynthetic rate (Pn).Under the three light intensity treatments,LCP and Rd were the lowest;LSP and light-saturated photosynthesis at ambient CO2 concentration (Pmax) were the highest in 30% of full light.L3 was showed Rhododendron ‘Furnivall’s Daughter’ the most appropriate growth light intensity.(2)With the reduction of light intensity,chlorophyll a was dropped slightly.However,the content of chlorophyll b,nitrogen in per unit area (LNCa) and photosynthetic nitrogen utilization efficiency (PNUE) were increased significantly.The influence of light intensity to chlorophyll b was more sensitive than that of chlorophyll a.As the results,total chlorophyll increasd obviously and the ratio of chlorophyll a/b decreased.(3)The plasticity analysis showed that Rhododendron ‘Furnivall’s Daughter’ adapted to the changes of light environment mainly through the changes of Pmax,LSP,LCP,Rd,PNUE and total chlorophyll.However,leaf mass per unit area (LMA),LNCa,malondialdehyde (MDA) and superoxide dismutase (SOD) had little contribution.