Effects of temperature, UV-light and magnesium on anthocyanin pigmentation in cocoplum leaves

This study aimed to understand factors affecting leaf pigmentation of the woody subtropical plant Chrysobalanus icaco, referred to as cocoplum. The effects of temperature, UV-light and magnesium treatments were examined at different developmental stages. Shoot growth intensity and chlorophyll concentrations increased while anthocyanin concentration decreased with rise in temperature. UV-a light had a slight effect on shoot growth, but no effect on the pigment concentration of the leaves. Anthocyanin concentration decreased while chlorophyll increased as leaves matured. The change in anthocyanin concentration was due to dilution of the pigment at the early stages of development and its degradation later on. In an attempt to inhibit anthocyanin degradation in maturing leaves, whole plants were treated with magnesium salts. Magnesium increased anthocyanin concentration two fold at the developmental stage at which degradation was detected in control plants. By controlling UV-a light via shading, applying magnesium treatments, growers may manipulate both plant height and colour, thereby increasing the horticultural value of the crops.