Effects of water deficit on the leaf water relations of pot-grown olive cultivars

Abstract

An experiment was conducted to investigate the water relations of potted young olive trees (Olea europaea L.) cultivar ‘Biancolilla’, ‘Giarraffa’ and ‘Nocellara del Belice’ during water stress and after relief from stress. The aim was to highlight the different responses of the three cultivars and obtain a decision-making aid for planning an efficient watering schedule for potted plants grown in nurseries. Leaf water potential (Ψ), relative water content (RWC) and conductance to water vapour (gL) were measured in three-year-old plants. All three olive cultivars were able to survive the severe stress imposed by withholding water for three weeks, but gas exchange was strongly impaired and recovery after rewatering was slow, resulting in a potential reduction of growth. The cultivars showed different responses to drought: ‘Giarraffa’ was the most sensitive, showing the earliest reduction in Ψ and the lowest recovery in gL. ‘Biancolilla’ showed higher gL, leaf hydration and Ψ under water deficit and appeared to be best adapted to drought. The behaviour of ‘Nocellara del Belice’ was similar to that of ‘Biancolilla’, and a particularly good recovery of gL after rewatering occurred.