MORPHOLOGY AND ULTRASTRUCTURE OF IMMATURE CEREAL-GRAINS IN RELATION TO TRANSPORT

The surfaces of the pericarps of wheat and barley grains, 15-30 days after anthesis, were examined. Stomata were found in the pericarp epidermis on the ventral side at the apical end in one variety of wheat and four varieties of barley. Layers which stained red with Sudan IV were observed on the pericarp epidermis and on either side of the testa in immature barley grains. The ultrastructure of these layers was investigated. It was concluded that the cuticular layer inside the testa is derived from the nucellus. The significance of these cuticular layers in relation to the supply of carbon dioxide to the photosynthesizing cells of the pericarp is discussed. The movement of photosynthate and oxygen produced in the pericarp is also considered. © 1979, Annals of Botany Company.