The application of selenium combined with gibberellin enhances the yield and quality of Chrysanthemum morifolium Ramat cv. Hangju

Abstract

The flowers of Chrysanthemum morifolium Ramat cv. Hangju (Hangbaiju) are taken as a traditional medicine and health promoting tea due to their flavonoids. Selenium (Se) and gibberellic acid (GA) affect the flavonoid content of C. morifolium. However, few studies have evaluated the effects of Se combined with GA on Hangbaiju. Here, two-year field experiments were conducted with Se (sodium selenite [Na2SeO3]) and GA (50 and 100 mg L−1) applications alone or in combination, and the treatments were denoted as CK, Se50, Se100, GA50, GA100, Se50+GA50, and Se100+GA100. Se and GA application decreased the leaf soluble sugar contents, increased the soluble protein contents, and enhanced superoxide dismutase (SOD) and catalase (CAT) activities. The enhanced SOD and CAT activities were more pronounced with GA applications alone than other treatments. Se and GA applications increased the flower yield of Hangbaiju, and the highest values were recorded with Se50+GA50 in 2017 and 2018. When Se was applied alone or in combination with GA, the soluble sugar contents in Hangbaiju flowers showed the same trend as the flavonoid content; when GA was applied alone, the opposite trend was recorded. This fact suggested that Se and GA application modulate plant allocation of photosynthates to different metabolic pathways. Se application alone or in combination with GA increased the Se and flavonoid contents; the highest values of soluble sugar, protein and water extract contents were recorded with the Se50+GA50 application in 2017 and 2018, and the results provide an innovative approach to enhance the yield and quality of Hangbaiju flowers.