© 1995 Heron Publishing—Victoria, Canada
Growth and water relations of three geographically separate origins of maritime pine (Pinus pinaster) under saline conditions
D. Loustau, S. Crepeau, M. G. Guye, M. Sartore and E. Saur
INRA, Laboratoire d'Ecophysiologie et Nutrition, BP 45, 33611 Gazinet cedex, France / Received September 19, 1994
Summary
Water relations and growth of maritime pine (Pinus pinaster Ait.) were investigated in 2-year-old seedlings of French (‘Landes’), Iberian (‘Iberian’) and Moroccan (‘Tamjoute’) origin
raised for 67 days in a flowing solution culture system containing 0, 50, 150 or 250 mM NaCl. Height growth, and stem, needle
and root dry matter were reduced by salinity with minor differences among geographic origins. Predawn needle water potential
was decreased by salinity and corresponded approximately to the osmotic potential of the nutrient solution. Stomatal conductance
was reduced according to the amount of salinity applied. Whole-plant hydraulic conductance was also reduced, even when expressed
on a root dry weight basis. The osmotic potential of xylem sap was five- to sixfold lower than that of the nutrient solution.
Seedlings of the most southerly origin (Tamjoute) exhibited a greater ability to decrease osmotic potential under saline conditions
than seedlings of more northerly origin (Landes and Iberian) as a result of higher mineral cation transport to the shoot.
Keywords:
geographic origin, hydraulic conductance, needle water potential, osmotic potential, salt stress, stomatal conductance.
