Acta Horticulturae 618: 281-290., ISHS 2003
Proc. XXVI IHC – Environmental Stress
Mechanism of Salt Tolerance of Two Olive
Olea europaea L. Cultivars as Related to Electrolyte Concentration and Toxicity
K. Al-Absi1, M. Qrunfleh *2 and T. Abu-Sharar 2
1 Mu’tah University , Fac. of Agric, Dept. of Plant Prod., Karak, Jordan
2 The University of Jordan, Faculty of Agric., Dept. of Horticulture and Crop Science, and Dept. of Land, Water, and Environment Amman, 11942, Jordan
Abstract
A pot experiment was conducted to investigate the response of 2 olive cultivars 'Nabali Muhassan' ( NM) and ' Frantoio' (F) to osmotic stress and specific chloride toxicity. The plants were irrigated with multicomponent electrolyte solution of increasing salinity and 2 ionic compositions. Irrigation water salinity was increased at 10 molc/m3 increment to a maximum of 100 molc /m3 at constant stiochiometric ratio of 1:1 and 3:1 for C1:SO4 or 1:1 for Ca:Mg and fixed Na adsorption ratio of 5. The solutions were applied at a rate sufficient to bring about a 30% leaching fraction when the tensiometer reading reached 50 cbar. The results indicated Na and Cl accumulation in leaf, shoot, and root of both cultivars significantly increased, however, K and Ca concentration decreased with increasing electrolyte concentration ( EC) of the irrigation water. Increasing proportion of Cl in the irrigation solution increased leaf Cl content. The F cv was more efficient than NM in restricting accumulation of Na and Cl in leaf. In addition, Mg content was not affected by the salinity stress. Exclusion of Na and Cl from leaves is the main mechanism of salt tolerance in F. Water use efficiency (WUE) of the two cultivars were drastically reduced with increasing Cl proportion and EC of the irrigation water. At high salinity levels, ‘NM’ was less efficient in using water. The present investigation demonstrates a considerable variability for salt tolerance in both olive cultivars and selection to salt stress is feasible by choosing a cultivar that has the ability to maintain a high K/Na ratio in its leaves; and that response to salinity stress is affected by interaction of cultivar, ionic composition and EC rather than the single effect of each.
Keywords: Olive, multicomponent electrolyte solution, Salt, Sodium, Chloride, toxicity.
