Glucosinolate enhancement in cabbage induced by jasmonic acid application

Glucosinolates (GSL) are bioactive compounds found in cruciferous vegetables that have been shown to have chemopreventive benefits for human health. The objective of this study was to determine whether foliar application of jasmonic acid (JA) increases glucosinolate accumulation and yield in cabbage (Brassica oleracea L. Capitata group). Field studies were conducted in 2004 and 2005 with a green ('Quisto') and red ('Ruby Perfection') cabbage cultivar. Foliar JA application rates were 0.1 mM, 0.2 mM, and split application of 0.2 mM JA with surfactant, surfactant control, and water control. Yield of both cabbage cultivars was not changed by JA application in both years of the study. In both years, 'Ruby Perfection' had significantly higher glucosinolate concentrations than 'Quisto' with sinigrin being the predominant glucosinolate in both varieties. JA application consistently increased sinigrin, gluconapin, and glucoiberin concentrations across cultivars and years of the study. JA application also increased progoitrin and total GSL concentrations, but the effect was inconsistent between years and cultivars. In most cases, a split application of 0.2mM JA resulted in the highest GSL accumulation. GSL accumulation was significantly higher in 2005 than 2004 for both cultivars. Climatic data suggest that annual differences in temperature may have influenced the variability in glucosinolate concentration in cabbage.