Drought-Adaptive Mechanisms of Young Sweet Cherry Trees in Response to Withholding and Resuming Irrigation Cycles

The present work evaluates the main adaptive mechanisms developed by young sweet cherry trees (Prunus avium L.) to cope with drought. For this purpose, were subjected two drought cycles different water stress intensities followed a recovery period. Three irrigation treatments applied: control treatment (CTL) irrigated ensure non-limiting soil conditions; moderate (MS) drying whose duration was dependent on time elapsed until reached values of midday stem potential (Ψstem) −1.3 and −1.7 MPa for first second cycle, respectively; severe (SS) similar MS, but reference −1.6 −2.5 MPa. In-between cycles, MS SS daily as CTL reaching Ψstem those trees. showed an important stomatal regulation lower vegetative growth. decreasing leaf turgor (Ψturgor) during periods accounted 40–100% reduction in at (Ψmd). minimum osmotic mature leaves about 0.35 than well-irrigated occasional adjustment observed not sufficient maintain Ψturgor or increase specific weight (SLW). insertion angle increased level increased. Severe (Ψstem < −2.0 MPa) resulted clear early defoliation further step conservation.