Physiological and cellular changes to coping with drought and low temperatures of olive (Olea europaea L.) in Patagonian steppe

ARIAS NADIA SOLEDAD; BUCCI SANDRA; SCHOLZ FABIAN; FIEDOROWICZ KOWAL RUTH; GOLDSTEIN GUILLERMO

San Juan

Simposio; VII International olive symposium; 2012

Olive trees have developed physiological mechanisms to tolerate drought and resist low temperatures. We evaluated sensitivity to low temperatures and resistance to drought in 5 varieties of olive during summer and winter in Patagonian steppe (45º 47?S, 67º 30?W). Two- years old- plants were grown outdoor in 20-dm3 pots irrigated bi-weekly. Electrolyte leakage method was used to evaluate cellular damage of mature leaves and determine LT50 (temperature for 50% of total ion leakage). Osmotic potential at turgor loss point (ψTLP), bulk elasticity modulus (ɛ) and solute content (Ns) were estimated from pressure-volume curves. Midday water potential (ψm) was measured in 10 leaves per season and variety. During summer Hojiblanca showed the lowest values of LT50 (-5.8°C), ɛ (2.03 ± 0.34 MPa) and ψTLP (-4.38 ± 0.72MPa). During winter all varieties increased their values of ɛ and decreased their ψm even when water content in the pots was high. Manzanilla showed the highest value of LT50 and the lowest value of solute content (-9.5°C; 0.157±0.014 respectively) while the other varieties showed the opposite trend from these variables. The temperature at which 50% of the total ion leakage, reflecting a 50% of loss in cellular intactness was positively correlated with ψTLP (R2=0.85,p