Characteristics of water consumption by transpiration of three common gardrn shrub species in Changsha,namely,Sabina vulgaris,Euonymus japonicus cv.Aureo-ma and Ligustrum vicaryi,were systematically studied by using such equipments as Lico 6400 Portable Photosynthesis System and BP-3400 Precision Balance.Finally indicated: The transpiration rates of the shrubs are low in the morning and dusk,high at noon as a single peak or double peaks.The transpiration rate of Sabina vulgaris changes gently in the diurnal variation;Euonymus japonicus cv.Aureo-ma and Ligustrum vicaryi changes a lot,both are low at 7:00-9:00 or 15:00-17:00,high at 11:00-15:00.The daily water consumption rate of Sabina vulgari and Euonymus japonicus cv.Aureo-ma in autumn are higher than it in summer but that of Ligustrum vicaryi in autumn is lower than in summer.Whether in summer or autumn,the daily water consumption rate of Sabina vulgari is the lowest among the three shrub species.

Water controlling experiment was conducted to study the transpiration rates of three shrubs species Loropetalum chinense var.rubrum Yieh,Rhododendron pulchrum,Gardenia jasminoides cv.prostrata by pot experiment under different soil water conditions.The results show that: The transpiration rates in normal water supply,L.chinense var.rubrum Yieh is 134.92g·m-2·h-1,R.pulchrum is 90.26g·m-2·h-1,G.jasminoides cv.prostrata is 87.16g·m-2·h-1 in slight drought stress,96.29g·m-2·h-1,34.98g·m-2·h-1 and 68.39g·m-2·h-1,respectively;in medium drought stress,75.97g·m-2·h-1,20.41g·m-2·h-1 and 41.48g·m-2·h-1,respectively;The shrub unit leaf suface water consumption,the transpiration rates: in normal water supply,L.chinense var.rubrum Yieh is 0.29kg·m-2·h-1,R.pulchrum is 0.92kg·m-2·h-1,Gardenia jasminoides cv.prostrata is 0.37kg·m-2·h-1;in slight drought stress,0.21kg·m-2·h-1,0.36kg·m-2·h-1 and 0.29kg·m-2·h-1,respectively;in medium drought stress,0.16kg·m-2·h-1,0.21kg·m-2·h-1 and 0.17kg·m-2·h-1,respectively.