HISTOLOGICAL STUDY ON TUBERISATION OF POTATO (SOLANUM-TUBEROSUM L) PROMOTED BY INHIBITORS OF GIBBERELLIN BIOSYNTHESIS

The application of antigibberellins to potato plant cultures results i n an accelerated tuber appearance, caused by stimulation of pith-,and cortex-cell growth, particularly in the radial direction. Their growth considerably precedes the initiation of parenchymatous cell divisions , which are the first steps of naturally occurrring tuberisation, regu lated by a different mechanism than the quantitative proportion of end ogenous gibberellins and cytokinins. Part of the cortex cells change t he orientation of their divisions to a periclinal one. The xylem paren chyma cells also undergo hypertrophy.