Senescence of date palm leaf and copper salts

Abstract

The changes in chlorophyll (chl) content of detached segments from four cultivars of date palm (Phoenix dactylifera L.) incubated in the dark for four days were investigated as affected by mono and divalent ions. Copper (CuH) and Zinc (ZnH) salts (acetate, chloride, nitrate and sulphate) as well as KCI were used in three concentrations (1~, 10"4, and 10-2 M). This study reveals that there is a specification effect on the retardation of Chl b senescence and enhance diminution of Chi a. The most effective ion in this system was Cu++, where at 10-2 M it enhances the degradation of Chl a and increases the relative amount of Chl b in all cultivars. Chl content in the four cultivars was also found to be different. It seems that CuH interacts with the protective mechanism of ChI a and causes the shift metabolism resulting in an increase of Chi b content relative to the control level.