Changes in some bioactive compounds of red cabbage (Brassica oleracea L.var.Rubra) under water stress

Abstract

A two-year study was performed on red cabbage (Brassica oleracea L.var.Rubra) to assess the effect of different irrigation levels on yield, sugar and organic acid contents. The study was conducted using drip irrigation system on a clay loam soil. The volume of irrigation water applied with 4-day intervals to each treatment was based on Class-A pan evaporation (Ep). In the full irrigation treatment (I1.0), a pan evaporation using screen covered Class-A pan was measured with 4-day intervals and all amount of evaporation was applied in the normal (1.00xEp) treatment, and deficit amounts were imposed on three irrigation treatments as I0.7 (0.7xEp), I0.3 (0.3xEp), and I0.0 (0.0xEp). The plant-available soil water at maturity and yield of red cabbage was significantly related to irrigation amounts. Imposition of deficit irrigation resulted in yield reduction, especially in the severe stress treatments I0.3 and I0.0. Therefore, yields were related linearly to irrigation. That’s why, if there is no water scarcity full water demand of red cabbage need to be compensated for the whole growing season. However, in the deficit treatment, total sugar and especially ascorbic, oxalic, tartaric and malic acid contents increased, and only lactic acid decreased, on the other hand there was no significant effect of different water levels on the content of citric acid.