The structure and composition of aleurone grains in the barley aleurone layer

Abstract

Cytochemical methods have been used in conjunction with light and electron microscopy to determine the nature of the inclusions in aleurone grains of barley aleurone layers. Two kinds of inclusions were found: (1) Globoids within globoid cavities which were not enclosed by a membrane: the globoids stained red with toluidin blue due to the presence of phytin, and with lipid stains; (2) Protein-carbohydrate bodies which stained green with toluidin blue. The characteristics of globoids and protein-carbohydrate bodies as seen in the electron microscope are described in detail using both glutaraldehyde- and permanganatefixed tissues. The protein-carbohydrate body was identified by silver-hexaminestaining; this was not caused by carbohydrate but by some component which stained green in toluidin blue and which also occurred in cell walls in a thin band adjacent to the cytoplasm. The characteristics of both bodies are discussed in relation to apparent confusion in their identities in previous electron-microscope studies.