© 1992 Oxford University Press
RESEARCH-ARTICLE |
Is The Special Callose Wall of Microsporocytes an Impermeable Barrier?
Plant Cell Biology, Unidad de Bioquimica Vegetal, Estacidn Experimental del Zaidln (C.S.I.C.) Granada, Spain
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During the course of cytochemical studies in sugar beet anthers (Beta vulgaris L.) to test the applicability of cerium methods for the ultrastructural localization of enzymatic activity in plant tissues, new evidence was obtained that questions the impermeability of the special callose wall surrounding the tetrad of microspores. Cerous ions, added to cytochemical media as a potential capture agent for enzymatically-produced hydrogen peroxide, showed binding to cell walls and plasma membranes exclusively in the zone of mechanical injury to the tissues, which may correspond to sites of hydrogen peroxide formation as a consequence of wounding. The cerium perhydroxide precipitate formed as a result of this reaction was localized within the cell walls of anther tissues, inside the callose surrounding tetrads of microspore and in the primexine layer of the microspore wall. The results of this study provide evidence for callose permeability in in vivo conditions, for at least some substances such as cerous ions or cerium perhydroxide.
Key words: Callose, cerous ions/cerium perhydroxide, permeability