夏季城市绿地中不同遮阳条件下杜鹃叶温变化及其生理响应

Influences of Different Shading on Leaf Temperature and Physiological Response to the Summer High Temperature of Rhododendron pulchrum

在自然高温条件下,从城市绿地中实地取样,观测了不同遮阳条件(全荫、半荫和全阳)下栽植的春鹃经历夏季高温产生的叶片形态损伤、叶温变化及其生理响应,研究比较了城市绿地不同遮阳条件对减弱杜鹃花品种"紫蝴蝶"夏季热害的作用。结果表明:叶温与环境光强变化呈正相关;全阳条件下的"紫蝴蝶"叶温明显高于半荫和全荫环境的"紫蝴蝶"叶片,夏季最高达40℃;全阳条件下的"紫蝴蝶"叶绿素和类胡萝卜素含量、细胞膜透性等生理指标均与半荫和全荫环境的呈极显著差异。结合"紫蝴蝶"叶片形态损伤和生理指标,证实全阳条件下的"紫蝴蝶"存在明显的夏季热害,而疏林环境下的半荫条件能有效减弱"紫蝴蝶"的夏季热害,是"紫蝴蝶"的适宜种植环境。

This experiment was conducted in high-tempered urban landscape to test the influence of different shading conditions （full-shade, semi-shade and no-shade） on the morphological damage,leaf temperature and physiological response of Rhododendron pulchrum leaves,different shading conditions on weakening heat damage in high-tempered summer were comparely studied. The results showed that the leaf temperature was positively correlated with light intensity thereby the leaves under no-shade condition could reach the maximum temperature to 40℃ in summer, significantly higher than the semi-shade and full-shade. The chlorophyll contents, carotene contents and membrane cell membrane permeability of no- shade leaves were also significantly different from leaves under other shade conditions. Thus, semi-shade condition was proved to be the most favorable condition for plant growth of Rhododendron pulchrurn spp..