Correlation between Bolting and Physiological Properties in Chinese Cabbage (Brassica rapa L. pekinensis Group)

Abstract

To obtain physiological data on bolting in Chinese cabbage (Brassica rapa L. pekinensis Group), we conducted seed vernalization treatment using six cultivars of Chinese cabbage with different maturity times, and an experiment on spring cultivation using eight strains with different bolting properties. Soluble sugar content and peroxidase (POD) activity in seedlings in the vernalization plot that were in the flower bud differentiation stage were high in early-maturing cultivars followed by mid-season cultivars; nitrate reductase (NR) and catalase (CAT) activities were high in early-maturing cultivars compared to the control, which did not encounter low temperatures. A correlation was recognized between bolting (number of days from sowing to bud emersion) and the values of soluble sugar content and POD, NR, and CAT activities in strains with different bolting properties during the differentiation stage 15 days before bud emersion. These results show that soluble sugar content and POD, NR, and CAT activities in the flower bud differentiation stage in Chinese cabbage participate in flower bud differentiation, and it is considered that these properties are physiological indicators of bolting.