Physiological role of glucosinolates in brassica napus. Concentration and distribution pattern of glucosinolates among plant organs during a complete life cycle

Concentrations and distribution of glucosinolates in various organs of rape (Brassica napus L) were examined during major stages of development. Fluctuations in the total content as well as in the individual levels of glucosinolates were investigated in double low Drakkar and high glucosinolate Chine 32 cultivars. The distribution pattern of aliphatic and aromatic glucosinolates between the various organs, as well as the variation in the concentrations of individual glucosinolates during plant development were quite similar between the two cultivars. Peculiar stages of accumulation during the vegetative growth period and the seed maturation period were identified. These stages were followed by periods of intense degradation during flowering, germination and early growth stages of seedlings. Fluctuations in the amount and structure of the glucosinolates in each of these periods suggest a storage function for these compounds which are required at specific stages of development. The involvement of some of these compounds in hormonal control of flowering is also discussed.