Response to sodium chloride in different species and clones of genus Populus L.

A greenhouse study was undertaken to evaluate the response to sodium chloride (control, 68 mM and 137 mM) of different species and genotypes of genus Populus L. (P. x euramericana (Dode) Guinier clones: 'I-214', 'Flevo', 'I-MC' and 'Triplo'; P. deltoides x P. alba clones: 'M30' and 'M31'; P. alba L. clones: 'Jalon-F-1-22', jalon F-1-4', 'Guadalquivir F-21-38','Guadalquivir F-21-39', 'Guadalquivir F-21-40' and 'Montanana F-2-9'; and P. eupbratica Oliv.). Survival, visual symptomatology, height growth, dry weight both in shoots and roots, photosynthesis rate and leaf concentrations of Na+, K+ and Ca2+ were evaluated. There were differences in survival between clones (0 per cent for the most sensitive and 100 per cent for the most tolerant) but growth was significantly reduced in all cases except for dryweight of P. eupbratica at 68 mM. The photosynthesis rate was significantly reduced in all clones at the end of the experiment (60 days) but not in the same way in the middle (30 days). The leaf levels of Na+, K+ and Ca2+ were also significantly different between clones. Intra- and interspecific variability have been detected in the genus, especially in P. alba.