Evidence of glyoxysomes in germinating pine seeds

Abstract

By means of differential centrifugation, assay of enzyme activity and electron microscopy, the occurrence of glyoxysomes was demonstrated in germinating Pinus pinea seeds. All the enzyme activities of the glyoxylate cycle were found in the glyoxysome fraction. The specific activity of isocitrate lyase, located in this organelle, increased during germination of the seed. Electron microscopy of three different zones of the endosperm showed a gradual disappearance of lipid bodies and aleurone grains while glyoxysomes, mitochondria and membrane systems increased during germination. The most abundant organelles in vacuolated cells were the glyoxysomes, which seemed to be closely associated with the rough endoplasmic reticulum.