Increased anthocyanin accumulation in ornamental plants due to magnesium treatment

Abstract

SummaryOne of the main external factors that influence anthocyanin accumulation is temperature, with low temperatures increasing and elevated temperatures decreasing pigment concentration. Recently we showed that higher magnesium levels increased anthocyanin accumulation in aster flowers grown at elevated temperatures, probably due to increased stability of the pigments. The aims of this study were to further characterise the effect of magnesium treatment on pigmentation in a variety of plants, and to determine the specificity of the treatment with respect to plants, plant organs and anthocyanins. Four ornamental plants that accumulate anthocyanins in different organs were chosen: Anigozanthos ‘Mini Ranger’ with red flower buds, Limonium ‘Blue Night’ with blue bracts, Gypsophila ‘Pinkolina’ with pink flowers, and Aconitum napellus with blue flowers. The plants varied in the specific anthocyanins that generate their colour. Magnesium treatment caused a significant increase in anthocyanin concentrations (between 15% and 70%) in all plants, with a stronger effect under elevated temperature regimes. Magnesium treatments were effective when given to whole plants, cut branches, or detached flower buds. Our results suggest that turnover of anthocyanins occurs in all four plants, and that stabilising the pigments may serve as a method to increase pigment concentration.