Seasonal changes in water relations and gas exchange in leaves of two Tunisian olive (Olea europaea L.) cultivars under water deficit

• Published in: The journal of horticultural science & biotechnology Vol. 82; no. 5; pp. 721 - 726
• Main Authors: Guerfel, M., Baccouri, B., Boujnah, D., Zarrouk, M.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 2007
• ISSN: 1462-0316; 2380-4084
• DOI: 10.1080/14620316.2007.11512296

Water relation parameters, leaf CO 2 assimilation rates, stomatal conductance (g s ), internal CO 2 concentrations (C i ), and stomatal density were studied in two major Tunisian olive cultivars, 'Chemlali' and 'Chetoui', under rain-fed, or rain-fed plus a moderate level of supplemental irrigation, conditions. Measurements were carried out throughout the season from January - September 2005, on 1-year-old leaves. CO 2 assimilation rates showed substantial seasonal variation, but were similar in the two cultivars, with higher values during the Spring and lower values during the Summer. Stomatal conductance (g s ) followed a similar trend to leaf CO 2 assimilation rates, with an increase in March, followed by a decrease during August. 'Chetoui' had the highest leaf CO 2 assimilation rate and g s value (24.26 µmol m -2 s -1 and 0.35 mol m -2 s -1 , respectively); but, compared to the supplemental irrigation treatment, 'Chemlali' had a higher resistance to drought stress than 'Chetoui'.