Leaf conductance was slow to recover in flooded plants (Fig. 3), reaching values similar to those of the control plants 5–8 days after Ψl had recovered (Fig. 2). This was particularly so in Búlida/RF plants in which gl recovered later than in Búlida/P plants.
Net photosynthesis showed a similar behaviour to that of gl, with overall values slightly higher in plants grafted on P than on RF rootstock. A greater reduction in Pn was observed in plants grafted on RF rootstock (Fig. 4 a, c). In T2 plants grafted on RF net photosynthesis reached negative after day 4 (Fig. 4 c). However Pn values recovered to reach control values more rapidly than gl (Fig. 3), coinciding with the recovery of leaf water potential values (Fig. 2). All flooded plants showed simultaneous decreases in Pn and gl, and an increase in internal CO2 concentration values (Table1). Flooding caused a downward growth of the petioles known as epinasty, which was statistically significant from day 6 of the experimental period in plants of both rootstocks (Table 1), whether in the T2 treatment (still immersed in water) or in the T1 treatment (during the recovery period). Epinasty was more pronounced in plants grafted on RF than on P rootstock (Table1).