Leaf recovery responses during rehydration after water deficit in two bean (Phaseolus vulgaris L.) cultivars

Our hypothesis was that recovery responses (RI and RII) upon rehydration, after 1 and 8 d of moderate (WDI) and severe water deficit (WDII), are evidence of tolerance in two commercial bean cultivars, Tacarigua (T cv) and VUL-73-40 (V cv). Recovery of leaf water (w) and osmotic potentials (s), and relative water content (LRWC), showed strong dependence on soil water potential (sw) followed by protein content; recovery connection between stomatal conductance and soil w is showed. Chlorophyll (a + b), Ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) activity, dry biomass (DM), and leaf area (LA) recovery were sensitive to WD intensity. Specific leaf area (SLA) and leaf density (D) recovery were less dependent on WD intensity and in time-dependent manner; V cv recovery was slower, showed faster recovery of Rubisco activity and DM due to slower recovery in SLA and D, which promoted it. Rubisco activity presented correlations with LRWC and w at moderate and severe WD in both cultivars, and significant correlation with s was observed in V cv. We conclude that recovery after rehydration reveals intrinsic tolerance to WD, due to an integration of metabolic and structural interactions, in responses to leaf water status components.