Changes in water relations, photosynthesis and leaf anatomy induced by intermittent drought in two olive cultivars

Photosynthetic rate, water relations parameters as well as leaf anatomical characteristics were studied in two olive cultivars (Olea europea, cv 'Koroneiki' and cv 'Mastoidis') grown under water stress conditions. No significant differences were obtained between the two cultivars concerning their ability for turgor maintenance under water stress conditions. 'Koroneiki' seems to maintain higher photosynthetic rates with lower values of stomatal conductance than 'Mastoidis', a fact that could be attributed to differentiation in leaf anatomy induced by water stress conditions. The fraction of mesophyll volume represented by intercellular air spaces as well as the surface area of mesophyll cell walls exposed to intercellular spaces was larger in 'Koroneiki' than in 'Mastoidis'. The possibility of using leaf anatomical characteristics as selection factors for olive cultivars grown under drought conditions is discussed. (C) 1999 Elsevier Science B.V, All rights reserved.