Sh. Zivdar - Department of Horticultural Science, Tarbiat Modares University (TMU), P. O. Box: ۱۴۱۱۵-۳۳۶, Tehran, Islamic Republic Iran.
K. Arzani - Department of Horticultural Science, Tarbiat Modares University (TMU), P. O. Box: ۱۴۱۱۵-۳۳۶, Tehran, Islamic Republic Iran.
M. K. Souri - Department of Horticultural Science, Tarbiat Modares University (TMU), P. O. Box: ۱۴۱۱۵-۳۳۶, Tehran, Islamic Republic Iran.
N. Moallemi - Department of Horticultural Science, Shahid Chamran University, Ahvaz, Islamic Republic Iran.
S. M. Seyyednejad - Department of Plant Physiology, Shahid Chamran University, Ahvaz, Islamic Republic Iran.

This study was conducted under Ahvaz, Iran environmental condition during ۲۰۱۲ and ۲۰۱۳ growing seasons in order to investigate the influence of foliar application of potassium on some physiological and biochemical characteristics of three olive cultivars including ‘Mission’, ‘Koroneiki’ and ‘Dezfuli’. Potassium sulfate in different concentrations of ۰, ۱, and ۲ g l-۱ was sprayed twice on selected mature ۱۰ year old trees; at ۵۰ and ۶۵ days after full bloom. Potassium sprays increased leaf chlorophyll content of all cultivars, leaf potassium content in ‘Mission’ and ‘Koroneiki’ cvs., fruit anthocyanin concentration of ‘Dezfuli’ in two crop seasons. However, K treatments had no significant effect on leaf N and P content, fruit K and P content in all studied cultivars. Fruit soluble carbohydrates increased by foliar application of potassium in ‘Koroneiki’ and ‘Dezfuli’ cultivars in the second year of study. Stem water potential and leaf stomatal conductance were significantly affected by cultivar and K treatments during the two years. Our findings showed that foliar application of potassium resulted in the decrease of stomatal conductance of ‘Koroneiki’ and ‘Dezfuli’ in two crop seasons. Based on the results, it can be concluded that the studied cultivars differently respond to K treatments during the two crop seasons and foliar potassium application could have a positive impact on leaf chlorophyll, leaf potassium, fruit soluble carbohydrates and fruit anthocyanins in olive cultivars.

Foliar application, olive, Potassium, Soluble carbohydrates, Stomatal conductance