WATER RELATIONS OF DIFFERENT Eucalyptus SPECIES UNDER VARIABLE SOIL MOISTURE REGIMES

摘要

Six months old seedlings often Eucalyptus species were grown for about 46 weeks under variable soil moisture conditions. The water use by the seedlings of E. camaldulensis (71.19), E. saligna (70,50) and E. urophylla 69.81 μgcm~(-2) sec~(-1)) showedrelatively higher transpiration rate, while E. ochrophloia had the lowest value of 57.98 iig cm-2 sec-1 during the month of May, The effect of soil moisture on transpiration rate was significant only in the month of May. The average diffusion resistancewas maximum in E, melanophloia, E. ochrophloia and E. exserta and these species had generally 2.5 to 3.0 times more diffusion resistance than E. melanophloia and 2.0 times more than E, saligna species. The effect of soil moisture on the diffusion resistance was significant at both the occation of observations and higher resistance was found under flooding treatments. The leaf temperature increased continuously with a decreasea in soil moisture in all the species of Eucalyptus: The transpiration rate andleaf temperature showed a close relationship with each other and both these parameters were inversely related with the leaf diffusion resistance.