WATER RELATIONS OF FINO LEMON PLANTS ON 2 ROOTSTOCKS UNDER FLOODED CONDITIONS

Potted two-year-old Fine lemon plants (Citrus limon (L.) Burm. hi.) gr afted on two different rootstocks: sour orange (C. altrantium) (SO), a nd C. macrophylla (CM) were submitted to two different treatments: non -flooded (control) and flooded for 8 days, under field conditions. Lem on/CM plants had lower plant plus soil resistance to water how (R((p+s ))) values for both treatments. The decrease in leaf water potential ( Psi(l)) and leaf turgor potential (Psi(p)) values, observed in the las t part of the flooding period, in both hooded scion/rootstock combinat ions, can be related to the increase in the resistance to water how. T he maintenance in Psi(l) and Psi(p) values in hooded plants at values similar to those of the control plants, at the beginning of the hoodin g period and during the recovery period, can be ascribed to the stomat al control observed (decrease in leaf conductance (g(l)) values). The later g(l) recovery in lemon/CM than in lemon/SO flooded plants, could explain the lower vegetative growth of lemon/CM plants by flooding ef fect. The observed g(l) response to soil flooding suggested that porom etry is a reliable indicator of the altered behaviour caused by floodi ng in lemon plant.