Lipids of the Common Pea (Pisum sativum L.) with Special Reference to the Occurrence of Galactolipids

Abstract

IT has been firmly established that the lipids of most seeds consist almost entirely of triglycerides¹. The lipids of leaves, on the other hand, are much more complex and contain considerable amounts of wax and phospholipids¹ in addition to a cold acetone-soluble fraction amounting to some 50–70 per cent of the total lipids². This acetone-soluble fraction has been generally assumed to consist mainly of triglycerides along with lesser amounts of unsaponifiable matter and free fatty-acids. In the light of recent work, however, it appears that leaves contain not more than minor amounts of triglycerides, their place being taken by galactolipids^3,4. The identification of galactolipids as the main lipid fraction involved in the early stages, of photosynthesis suggests a relationship between the occurrence of chlorophyll and of galactolipids⁵, and is in keeping with their presence in leaves and their apparent absence in seeds. In this regard it was thought instructive to examine the leaves, pods and seeds of the common pea (Pisum sativum L.) as the seeds in this instance contain relatively little oil, much of which is non-glyceridic in nature⁶, and in addition the seeds contain some chlorophyll or chlorophyll-like pigments.