INCREASED ANTHOCYANIN ACCUMULATION IN FLOWERS AND FOLIAGE AT ELEVATED TEMPERATURES IS AFFECTED BY MAGNESIUM TREATMENT

Elevated growing temperature is one of the main external factor causing a decrease in anthocyanin accumulation in plant tissues. In many cases, the economic success of ornamentals depends on the quality of pigmentation, and faded colours decreases product value. In a study comparing two aster cultivars, ‘Sungal’ and ‘Suntana’, we have shown that an elevated temperature caused colour fading of one (‘Sungal’) but did not influence the pigmentation of the other (‘Suntana’). However, increased temperature caused a decrease in the activity of anthocyanin synthesizing enzymes in both cultivars. Therefore, the difference between the lines must be in the stability of their pigments at elevated temperatures. Several metals have shown to increase the half-life of anthocyanins, by forming complexes with them. We studied the combined effect of elevated temperatures and increased metal concentrations on the accumulation of anthocyanins in aster and anigozanthos flowers. It was found that magnesium of ‘Sungal’ aster and ‘Mini Rager’ anigozanthos flowers, partially prevented faded colouring at elevated temperatures. In addition, magnesium decreased the rate of anthocyanin degradation in Chrysobalanus icaco (cocoplum) leaves.

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