武汉市51种园林植物的气体交换特性

对湖北武汉市5个绿地共51种园林植物的气体交换特性的研究表明: 不同绿地间、灌木与乔木间、落叶与常绿植物间的光合能力(A_max)、蒸腾速率(T_r)和光合水分利用效率(PWUE)均有显著差异。绿地间的气体交换特性差异主要表现在物种间, 不同绿地间的小气候或环境差异影响很小。根据51种植物的A_max、T_r和PWUE, 可将它们划分为3大类群。其中大部分植物属于低光合低水分利用型(38种), 其次为高光合高蒸腾型(10种), 低耗水高水分利用型最少, 仅有花榈木(Ormosia henryi)、银木(Cinnamomum septentrionale)和黄心夜合(Michelia bedinieri) 3种。

Gas exchange characteristics of 51 garden species in Wuhan City,China

Aims Garden plants account for the main part of urban green spaces, and their gas exchange is the key ecological process for regulating urban ecosystem function. Our objectives were to determine whether there are significant differences in gas exchange characteristics among different green spaces and plant guilds in Wuhan City, China and to explore how different environmental conditions and species composition affect these gas exchange characteristics.Methods Photosynthetic capacity (A_max), transpiration rate (Tr) and photosynthetic water use efficiency (PWUE) were measured for 51 garden species in five green spaces in summer, using a portable photosynthesis system (CIRAS-2, PP systems, Amesbury, USA).Important findings There were significant differences in A_max, Tr and PWUE among green spaces, shrubs and trees and deciduous and evergreen plants. However, the variation among green spaces was mainly related to differences among species and to a minor extent to differences in microclimate. Based on these gas exchange parameters, the species studied can be divided into three groups: low photosynthesis and low water use efficiency species (38 species), high photosynthesis and high transpiration species (10 species) and low water consumption but high water use species (Ormosia henryi, Cinnamomum septentrionale and Michelia bedinieri).