Influence of fertilisation on anthocyanin accumulation and acylation in Brassica oleracea

Abstract

ABSTRACTA wide range of factors including biotic and abiotic stresses influence anthocyanin accumulation in plants. In this study, experiments were designed to measure the effects of nutrient depletion on anthocyanin accumulation in 3-week old juvenile Brassica oleracea seedlings of the red cabbage cultivar ‘Futurima’ and the red kale cultivar ‘Redbor’ that were grown in a hydroponic system. The effects of the depletion of single nutrients were compared to standard fertigation conditions. Plants were grown for 2 weeks in the absence of nitrogen accumulated higher anthocyanin levels than in all other treatments in both ‘Futurima’ and ‘Redbor’. Nutrient depletion treatments significantly influenced the percentage of anthocyanin diacylation in ‘Futurima’, but not in ‘Redbor’. A time-course experiment revealed that juvenile cabbage and kale seedlings accumulated maximal anthocyanin concentrations after 18 days without a supply of nitrogen. ’Redbor’ chromatograms were influenced by the localisation of anthocyanins in plant tissues, while nitrogen depletion treatments significantly increased anthocyanin concentrations in stems and leaves. In both greenhouse and growth chamber conditions, nitrogen depletion treatments in ‘Redbor’ significantly increased the percentage of diacylated anthocyanin compounds compared to control treatments in stems but not in leaves. These findings will help to optimise anthocyanin production in juvenile Brassica oleracea plants.