Tolérance au chlorure de sodium et sélectivité Na/K chez 3 races géographiques de pin maritime (Pinus pinaster Ait)

Abstract

Because of a maritime pine forest dieback on the west coast of France, 3 geographic provenances were tested for their tolerance to sodium chlorure and for their Na/K selectivity. Young seedlings (1 month old) were cultivated on aerated nutrient solution containing NaCl (0 to 150 mM/l). After 10 days of treatment, the 3 provenances differed in their sensibility to salinity, and the observed classification was found to be identical to the behavior of the trees in forest: this result supports the hypothesis of sodium as one of the factors responsible for the dieback. For these young plants, tolerance to Na was essentially due to a higher selectivity for K over Na, so that growth was maintained. A greater production of biomass would also allow these genotypes to delay the toxic effects of Na, by dilution of this cation. These physiological mechanisms, noted at an early growth stage, are to be confirmed on older plants. © 1995 Elsevier/INRA.