Abstract

Fluorescence parameters, xylem hydraulic properties, polyphenolic contents and antioxidant activity were studied on Two Tunisian olive cultivars (Ouslati, Jarboui) grown under water deficit conditions. Our results showed that water stress caused a decline in chlorophyll content, maximum quantum yield of photosystem II (Fv/Fm), linear electron transport rate (ETR) and quantum efficiency of PSII electron transport (ΦPSII). Oueslati variety was less affected by water stress but all these parameters decreases considerably in Jarboui variety. In addition, water stress induced an increase in xylem vessel frequency. The phenolic and flavonoid contents as well as antioxidant activities increase in the two cultivars under water stress conditions. Oueslati cultivar may be considered as the most tolerant cultivar showing the highest phenolic (43.65 mg GAE/g) and flavonoid (18.87 mg CE/g) contents and had the best antioxidant activity by both DPPH and ABTS methods with antioxidant activity of respectively 84.56% and 82.1%.