Response of three white poplar clones to salinity

Three white poplar clones (MA-104, MA-195 and O.Gherib), differing in their sensitivity to NaCl, were selected following a preliminary study. The young plants of these clones were subjected to three treatments: control, 3 g/l and 6 g/l of NaCl. A reduction-which varied according to the clones and salt concentrations-in height, diameter and total and compartmental biomass was observed in all three clones. At the leaf level, a reduction in leaf area and elongation rate, and an increase in epinasty, were also observed. However, these disturbances were less pronounced in plants of the MA-104 clone, indicating their greater salt tolerance compared with the other two clones. Similarly, the improved water-regulating behaviour of MA-104 resulted in the maintenance of the base, midday and recovery water potentials at relatively low levels, thereby helping to minimise the damage caused by salt. In contrast, the other two clones, particularly O.Gherib, suffered greater damage from salt.