Adv. Hort. Sci., 2009 23(2): 101-107

Growth and ionic relations in ‘Nabali’ olive during salinity stress as affected by salicylic acid and relief treatments

Khalid M. Al-Absi

Department of Plant Production, Faculty of Agriculture, Mu’tah University, P.O. Box 7, 61710 Jordan.

Abstract

The response of ‘Nabali’ olive plants to salt stress relief or exogenous salicylic acid (SA) pre-treatment under short-term salinity to improve salt tolerance was investigated. Transplants of ‘Nabali’ olive grown in plastic pots in sandy loam soils and irrigated with a nutrient solution supplemented with multicomponent electrolyte solutions were used. Irrigation water salinity was increased at 20 molc/m3 increments to a maximum of 120 molc/m3 at a constant stiochiometric ratio of 1:1 for Cl:SO4 and 1:1 for Ca:Mg and fixed sodium adsorption ratio (SAR) of 5. Number of new shoots, leaf area, dry weights of shoot and root and relative growth rate were reduced progressively by higher salinity levels. Leaf and root Na and Cl contents increased by salinization. Root content of both Na and Cl tended to be higher than those of leaf. During the period of relief from stress, a partial recovery of growth was detected. In addition, although leaf Na and Cl contents in leaf and root continued to increase as electrolyte concentration increased, a considerable decrease in their accumulation was observed, compared to corresponding salt concentrations, during recovery. SA pre-treatments partially diminished the inhibiting effect of salinity on growth of olive plants. SA pre-treatments reduced Na and Cl concentrations of leaves and roots, and prevented toxic effects of salinity because less Na and Cl accumulated in leaves and roots. These results suggest that the use of relief and SA pre-treatments may be useful methods to increase salt tolerance in olive on a long-term basis, for use in arid and saline environments.

Key words: chloride, growth, leaf, Olea europaea L., root, sodium.