| heal.abstract |
Although drought resistance varies among olive cultivars, their response to water stress has not been thoroughly investigated. The purpose of this study was to determine the effects of water stress on CO 2 assimilation rates (A) and stomatal conductance (g s) of 10 olive cultivars. Three-year-old olive plants (Olea europea L.) were grown outdoors in 70-L pots in a soil:peat:sand mixture. Ten plants per cultivar were placed in five plots, in a randomized complete block design. Control plants were irrigated every 2 days, water-stressed plants every 10 to 15 days during the dry season. G s and A were measured using a portable infrared gas analyzer. Results showed that cultivars 'Megaritiki', 'Chalkidikis' and 'Valanolia' had the highest A values, followed by cultivars 'Koroneiki', 'Adramitini', 'Kalamon' and 'Koutsourelia', while cultivars 'Amfissis', 'Arbequina' and 'Mastoidis' had the lowest A values. During the first drought cycle, the reduction in A and g s values was much smaller in 'Mastoidis', 'Adramitini' and 'Megaritiki' than in the other cultivars. Similar results were obtained during the second drought cycle for most cultivars, in particular 'Mastoidis' and 'Adramitini'. The results indicated that 'Mastoidis', 'Adramitini' and possibly 'Megaritiki' have a better ability to maintain higher CO 2 assimilation rates compared to the other cultivars studied under conditions of water stress. The possible mechanisms of this better adaptation are currently being investigated. |
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