No abstract

Almost all plant seeds accumulate storage proteins which are utilized by the developing embryo on germination. In wheat grain, the protein is formed predominantly in the endosperm tissue. Jennings & Morton (1963a, b) and Graham, Morton & Simmonds (1963a) have described the changes in the protein, carbohydrate, nucleic acids and other components during development of the endosperm of several varieties of wheat (Triticum spp.) grown under field conditions in South Australia. During development of the endosperm from about 10 days after flowering until maturity at about 40 days there is rapid synthesis of protein; in variety Dural, for example, the protein nitrogen increased from 54,tg./grain at day 12 to 558,ug./

Summa1'yFluorescence microscopy of thin sections of developing wheat endosperm previously fixed with osmium tetroxide and stained with acridine orange was used to study cellular development. Starch fonnation is predominant in the early period after flowering. The fine structure of developing endosperm cells was studied by electron microscopy of thin sections fixed and stained with osmium tetroxide or with potassium permanganate, or with formaldehyde followed by potassium permanganate. In addition to starch granules, numerous dense spheroidal bodies were observed. The staining reactions and the increase in numbers during growth indicated that the bodies probably consisted of storage protein. Observations on the occurrence of these protein bodies were made with three wheat varieties during two growing seasons (1959 and 1960). Based on the cytological evidence, the origin and intracellular localization of protein bodies is discussed.