Effect Of Sap Salinity On Hydraulic Properties Of The Stem Xylem Of Paraserianthes Lophantha Grown In Desert Region

Résumé: Previous researches have shown that the hydraulic conductivity may be significantly increased with increasing ion concentration in the xylem sap. The main purpose of the present study was to investigate the impact of sap salinity on the hydraulic properties of Paraserianthes lophantha that grown in desert region. Isolated stem segments were used to (1) determine the changes in lateral hydraulic conductance when xylem fluid was changed from deionized water to salt solution; (2) evaluate the variation in the degree of intervessel contacts by changing the sap salinity; and (3) visualize the variations in the lateral vessel contacts by using a double-staining method. The results showed that the hydraulic conductance was significantly increased when changing from deionized water to salt solution. The degree of intervessel contacts was somewhat increased by salinity, and this was visually confirmed by observation of some new lateral contacts between vessels in the double-staining experiments. The results indicated that the degree of lateral contacts between vessels could be changed under sap salinity by increasing the porosity and permeability of intervessel pit pathways. Our results may contribute to understand the effect of salinity on the hydraulic properties of xylem in the desert species.

Publié dans la revue: Journal Algérien des Régions Arides