Drought is a major environmental constraint affecting photosynthesis and production of olive trees in Tunisia. Transpiration and leaf water relations of mature olive trees (Olea europaea L. cv. Meski and Picholine) in relation to long-term water deficit (from March to October) were investigated in a research field in Kairouan, Tunisia. Olive trees were subjected to two irrigation regimes: T1 and T2 that received 100% and 50%, respectively of crop evapotranspiration via a drip irrigation system. Measurements were taken during a 3-week period in the summer at the end of the irrigation cycle (August). Prolonged drought significantly affected soil water content, sap flow, leaf water status, but the response differed between cultivars. In the stressed treatment (T2), midday leaf and xylem water potential dropped from -2.1 to -2.8 MPa and from -1.4 to -2.2 MPa respectively. Sap flow measurements show that for the Meski, water stress decreased sap flow by about 50%, but the Picholine reduced by only 25%. Hydraulic conductances in plant and soil-root-leaf pathway were more sensitive to water stress in Meski than in Picholine. We infer from these results that deficit irrigation (50% ETc) in Picholine cultivar reduced the consumption of water, while maintaining the good physiological activities of plant.

drought, drought resistance, evapotranspiration, hydraulicconductivity, leaves, olives, roots, sap flow, soil water content,stress, stress response, transpiration, trickle irrigation, waterdeficit, water potential, water stress, xylem, Tunisia, Olea europaea,Olea, Oleaceae, Scrophulariales, dicotyledons, angiosperms,Spermatophyta, plants, eukaryotes, Maghreb, North Africa, Africa,Mediterranean Region, Developing Countries, Threshold Countries,Francophone Africa, drought tolerance, Oleales, sap ascent,Horticultural Crops (FF003) (New March 2000), Plant Water Relations(FF062), Plant Production (FF100), Environmental Tolerance of Plants(FF900), Soil Physics (JJ300), Soil Water Management (Irrigation andDrainage) (JJ800) (Revised June 2002) [formerly Soil Water Management]

• Journal Article

• Drought
• Irrigation Management