The plant species used for urban greenery in arid and semi-arid regions have low species diversity and most of them are tender to drought and have high water requirements. The present study designed, to select the drought resistant species according to their leaf water potential (LWP) to cultivate in Isfahan greenery or forestry on arid and semi-arid regions. Two different sets of the experiments were handled, one on cultivated condition in-research Farm of natural resources department of IUT and the other on the Natural condition in four forest regions of Zagros and Albours Ranges during 2004 and 2005. The Farm experiment was planned with 5 various irrigation regimes: 40, 60, 80, 100 and 120 % of evaporation from a class A evaporation pan; in 2 different medias, a Good garden soil and a poor hillside soil that 10 broadleaves tree and shrub species was cultivated in a factorial experiment in randomized complete design with 5 replications. Two years data of this study were analyzed as compound analysis. The result showed that there are significant differences between the two soils, the plant species, the irrigation regimes and the two years measurements for the LWP amount. The average amount of LWP in the poor hillside soil was less than the Good garden soil. The reason for significant differences between soil and species interaction for LWP amount was the different reaction of plants species in two soil types. The Quercus infectoria and Populus alba in Good garden soil had the least and the highest amount of LWP. Regression analysis between the amount of irrigation water and LWP amount showed that the increases on amount of irrigation water results increases in LWP amount as well. Among the studied trees and shrubs species in the cultivated condition the Quercus infectoria had the least LWP amount (-3.9Mp) and the Populus alba had the maximum LWP amount (-
