Localization of and changes in pectic substances in the strawberry crown during flower-bud development

Localization of and changes in pectic substances in the crown cells of two strawberry cultivars during flower-bud development were investigated. Sections of crowns treated with and without 1% pectinase and stained with the periodic acid-Schiff reagent were compared. 1. At the vegetative stage, most granules in the untreated cells and pectinase-treated ones were equally stained. During the early stage of pistil differentiation, most granules in the untreated crown cells became stained, whereas those in the pectinase-treated ones did not. Thus, the granules in the cells during the early stage of pistil differentiation are composed of polysaccharides containing pectic substances which signify that pectic substances accumulate not only in the cell wall but also in the cytoplasm. 2. The total uronic acid which was traced during flower-bud development scarcely changed between the vegetative stage and the early stage of pistil differentiation. But pectic substances in the cytoplasm increased concurrent with flower-but development which we attribute to their migration from the cell walls.