CHANGES IN LIPID-COMPOSITION DURING FLORAL DEVELOPMENT OF BRASSICA-CAMPESTRIS

Apical tissues of Brassica campestris, grown under controlled environm ental conditions, were analysed for their lipid content. The principal lipids were sterols, phospholipids and sphingolipids. The major stero ls were identified as sitosterol, stigmasterol, campesterol and choles terol, the phospholipids as phosphatidylethanolamine (PE) and phosphat idylcholine (PC), and the sphingolipids as cerebrosides. In the early stages of apical development, unusually high proportions of cholestero l and cerebrosides were found. However, their relative proportions gra dually decreased as the apex developed; a concomitant increase in sito sterol was observed. These results suggested a specific association be tween these lipids and the development of the shoot apex. PE increased steadily during apical development, whereas PC increased more rapidly , but then declined at the later stage. The relative proportion of cam pesterol increased in the apex during the late stages of development a nd appeared to be involved in petal formation, which coincided with th e decrease in PC.