| Hunan Province is plagued by a seasonal shortage of water resources, but green spaces in city consume a large amount of water resources each year. For a long time, due to low awareness of the water consumption law for plants, irrigation management of green spaces is blind which causes huge waste of water resources. By taking dominant garden plants in Hunan as its object, improving utilization efficiency of water resources as its goal, this thesis focuses on tests of potted seedlings including 6 shrubs species such as Rhododendron pulchrum and environmental factors. Based on these research results, the author concludes the fluctuation law of water consumption for these trees species, makes a water consumption comparison among the different trees, builds up a relationship model between water consumption and dominant environmental factors and makes a scaling up. The following is the main results obtained in this research:It is the primary purpose of this work to compared with the water consumption in different shrubs species. With sufficient water supply, the difference of daily water consumption is big, from high to low are Euonymus japonicus cv.Aureo-ma>Loropetalum chinense var. rubrum Yieh>Ligustrum x vicaryi>Gardenia jasminoides>Rhododendron pulchrum> Sabina vulgar is.Water consumption of all kinds of species between different month was discovered. With sufficient water supply, the water consumption is reduce from October to November, except Ligustrum x vicaryi.The influence of environmental factors on trees transpiration is analyzed. With sufficient water supply, stomatal conductance and sun radiation have a strong influence on transpiration speed of all kinds of species, while relative humidity and temperature have relatively weak influence on transpiration speed.6 optimal models of transpiration speed and environmental factors are created.Standard for the grade-management of the space irrigation is established. According to physiological and outside characteristics of all kinds of trees with different water supply, during tests soil water-storage capacity is 20.4%(water potential-0.09 MPa), effective threshold value of soil moisture is 17.6%(water potential-0.26 MPa), threshold value is 12.8%(water potential-1.56 MPa), and if soil moisture is less than 118%(water potential-2.27 MPa), plants will languish permanently. The grade of landscape gardening maintenance is as following:special grade:17.6%～20.4% soil moisture with water potential-0.26 Mpa～-0.09 MPa; grade 1:12.8%～17.6% soil moisture with water potential-1.56 Mpa～-0.26 MPa; grade 2:below 12.8% soil moisture with water potential-1.56 Mpa.The scaling-up method of water consumption for trees is found. Water consumption of shrubs is calculated by scaling up leaf area index, and water consumption of individual tree is calculated by scaling up the correlation model of diameter and water consumption. Based on these results, water consumption of trees and soil can be calculated according to different cultivate style.During half a year observation, some advanced instruments such as Li-6400 Portable Photosynthesis System and SEC are used. In addition, in order to obtain precise data there are 3-5 parallel tests for each test project integrating with long time-span observation and multitemporal observation.In this thesis, water consumption research is introduced to green spaces in garden. It is the first time to combine the water consumption with the species selection and collocation of low water consumption in Hunan Province. The highlights of this thesis lie in the selection of research object, research system and integrating theory with practice.
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