The water relations of hemlock (Tsuga canadensis). I. Some equilibrium water relations as measured by the pressure-bomb technique

摘要

Theoretical and experimental aspects of the equilibrium water relations of excised hemlock (Tsuga canadensis) shoots are examined. The equilibrium water relations of hemlock were determined by using the pressure-bomb technique on shoots 15 to 40ensp;g in fresh weight. At or near full turgor the osmotic pressure of the cells averages 16.5ensp;+ensp;0.4 bars. The fraction of the total water content of hemlock shoots residing in the living cells is 0.77ensp;+ensp;0.04. When hemlock shoots are near full turgor the balancing pressure will change linearly with the volume expressed provided the volume changes represent less thanof the total shoot water content.