北京3个园林观赏树种苗木耗水特性初探

利用Li-6400便携式光舍仪和BP-3400天平等仪器。对北京市常用园林观赏乔木白玉兰Magnolia denudata．鹅掌楸Liriodendron chinense和刺槐Robinia pseudoacacia的蒸腾耗水特性进行研究。结果表明：春季的蒸腾速率大于夏季和秋季，3个树种日平均蒸腾速率分别为春季2．32，2．23和1．85mmol·m^-2．s^-1，夏季1．61,1．58和1．46mmol·m^-2．s^-1．秋季1．67，1．66和1．47mmol·m^-2·s^-1；3个树种均为春季耗水型，日平均耗水率分剐为春季2．2846，1．9529和1．1237kg·m^-2·d^-1，夏季1．0668，0．9658和0.3007kg·m^-2·s^-1，秋季1．1300，0．7837和0．4466kg·m^-2·s^-1；3个树种年平均日耗水率分别为1．4938，1．2341和0．6236kg·m^-2·s^-1，由年平均日耗水率可见，3个树种耗水能力由大到小依次为白玉兰、鹅掌楸和刺槐。图4表1参19

Water consumption and transpiration for seedlings of three ornamental tree species in Beijing

The objective is to contribute to the theoretical basis for reasonable selection of greening tree species and its water management. Water consumption characteristics due to transpiration for three ornamental tree species; namely Magnolia denudata, Liriodendron chinense, and Robinia pseudoacacia; were systematically studied in Beijing using a Li-6400 Portable Photosynthesis System and BP-3400 precision electronic balance. Results showed that 1 ） the spring transpiration rate of these three trees was higher than summer and autumn; 2） daily water consumption for these species was greatest in spring; and 3） the annual average daily water consumption rates were in the order： M. denudata （1.493 8 kg·m^-2·d^-1） 〉 L. chinense （1.234 1 kg·m^-2·d^-1） 〉 R. pseudoacacia （0.623 6 kg·m^-2·d^-1）. The rate of annual average daily water consumption is important for evaluating the water consumption capability of a tree.[Ch, 4 fig. 1 tab. 19 ref.]