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.