The Correlation Between Shade Tolerance and Leaf Characteristics of Ten Urban Landscape Plants

摘要

To investigate the shade tolerance index of ornamental flowers and trees, this study conducted a comparison of leaf morphological characteristics in various shade tolerant plants under different shading levels. According to the light compensation point, ten common ornamental plants were classified into two groups: shade tolerant plants (light compensation point under 25 μmol m~(-2) s~(-1)) such as Aglanonema modestum, Camellia japonica, Ternstroemia gymnanthera, and Schefflera arboricola; and shade intolerant plants (light compensation point over 26 μmol m~(-2) s~(-1)) such as Bougainvillea spectabilis, Prunus campanulata, Cassia surattensis, Lagerstroemia indica, Durante repens, and Bauhinia variegate. Two months after these plants were treated with 0%, 30%, and 85% shading; the morphological characteristics of the leaves were recorded. The results showed that the leaf water content of shade intolerant plants increased obviously, when light intensity was decreased. Comparatively, light compensation point value, specific leaf fresh weight, and leaf thickness decreased significantly. The regression analysis of relationships between light compensation point and morphological characteristics showed that light compensation point and specific leaf fresh weight have the most significant correlation (r = -0.7171*) under 85% shading environments. Furthermore, in comparison of light compensation point to relative leaf characteristic data, light compensation point was markedly correlated to relative specific leaf fresh weight (85%/0%, r = -0.8493**) and relative leaf thickness (85%/0%, r = -0.8071**). Therefore, we suggest that relative specific leaf fresh weight, which is more highly correlated to light compensation point than specific leaf fresh weight, is a new and precise method for determining shade tolerance of ornamental flowers and trees.