PRELIMINARY ATTEMPTS AT ULTRASTRUCTURAL POLYSACCHARIDE LOCALIZATION IN ROOT TIP CELLS

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Abstract
A basic method and many variations are described which initially appear to give good ultrastructural localization of polysaccharide material and also sulfhydryl groups in sections of plant tissues. Using permanganate fixation, alkaline silver hexamine solutions very strongly stained cell walls and starch grains (if they survived the treatment) in thin sections; in root cap and epidermal cells, Golgi bodies and associated vesicles also strongly reacted. The reaction was markedly reduced if sections were pretreated with aldehyde-complexing reagents (dimedone, etc.) and reintroduced after such blocking reactions by further periodate oxidation. Apart from a variable unspecific argentophilic reaction of manganese in the sections (which does not appear if the manganese is leeched out), other components of the cells showed very little staining in permanganate-fixed cells. Differences were noted between the reactivity of various polysaccharides. A strong generalized staining reaction was observed over sections of glutaraldehyde-fixed tissues, and this could be almost entirely blocked by pretreatment of the sections with iodoacetate; such treatment also indicated that there were comparatively few aldehyde groups present, either native and/or introduced by the fixative. Periodate oxidation then introduced staining groups in some Golgi bodies and cell walls, particularly in epidermal cells.