Turgor maintenance in leaves and roots of ‘Colt’ cherry trees (Prunus aviumXpseudocerasus)in response to water stress

SummaryPressure-volume methodology was used to evaluate the components of plant water potential in expanding leaves, mature leaves and roots of well watered and water stressed plants of Prunus avium x pseudocerasus ‘Colt’. Under well watered conditions, expanding leaves, mature leaves and roots lost turgor at water potentials of -1.37, -1.84, and -1.12 MPa, respectively. Comparable tissue from water stressed plants maintained turgor to^water potentials of —2.08, —2.09, and —1.85 MPa. This improved capacity for maintaining turgor resulted primarily from changes in tissue osmotic potential and was not due to changes in tissue elasticity. Regardless of the imposed water regime, roots lost less turgor for a given change in tissue water potential than did leaves. As compared with leaves, the more elastic root tissue compensated for higher tissue osmotic potentials at full turgor by allowing for a greater reduction in relative water content and concentration of tissue solutes as water potentials decreased, thereby reducing the rate at which turgor was lost.