Germination of phaseolus vulgaris I. Resumption of axis growth

Abstract

Growth of the excised axis of Phaseolus vulgaris L. (var. White Marrowfat) begins after a 7-hour incubation in buffer or water at 26 degrees . Growth, as measured by axis elongation or fresh weight increase, is linear for at least 8 hours with a resultant fresh weight increase of approximately 65%. Cell elongation begins 4 or 5 hours prior to cell division and 5 or 6 hours prior to radicle protrusion in the intact seed.The initiation of axis elongation is apparently dependent on synthesis of RNA and protein. Both actinomycin D and puromycin inhibit the initiation of elongation. Actinomycin I) inhibits the incorporation of ATP-8-C(14) into axis RNA and C(14)-leucine into protein, while puromycin inhibits the incorporation of C(14)-leucine into axis protein.The respiratory rate of the axes increases sharply at about the time of initiation of cell elongation. Dinitrophenol initially increases O(2) uptake by the axes, but at the end of 15 hours the rates of O(2) uptake by control or dinitrophenol-treated axes are approximately the same.