THE EFFECT OF EPIBRASSINOLIDE ON ULTRASTRUCTURAL AND MORPHOMETRIC CHARACTERISTICS OF APICAL CELLS IN POTATO-TUBERS

Methods of electron microscopy and morphometry were used to study alte rations induced by the treatment of potato (Solanum tuberosum L.) tube rs with epibrassinolide-694 (EB) in the cell ultrastructure of differe nt apical regions. The effect of EB treatment depended on the specific ity of both the apical region and individual subcellular structure. Ce ntral and rib meristems were the most sensitive to EB. In these tissue s, EB treatment drastically changed cell morphology and led to an incr ease in the length of rough endoplasmic reticulum. Sprouting-inhibitin g EB concentrations damaged the mitochondria, but did not influence th e plastids themselves or their proliferation in apex cells.