Certain Factors Influencing Expression of the Flowering Stimulus in Xanthium. Part II. Relative Contribution of Buds and Leaves to Effectiveness of Inductive Treatment

Abstract

1. By means of appropriate defoliation, flowering may be confined to the donor (short-day) branch and denied to the receptor (long-day) branch of a two-branched Xanthium plant during the photoinductive treatment of the donor or for any desired interval after the photoinductive treatment has been terminated. Debudding the donor, removing the mature leaves of the receptor branch, and allowing growth of the young leaves of the receptor branch all contribute to movement of the flowering stimulus from the donor branch to the receptor buds. The results of experiment I indicate that (a) the stimulus remains stable within the plant and is available to the receptor buds for considerable periods after inductive treatment of the donor has been terminated and (b) the stimulus may be stored in the young leaves and/or the buds. 2. Appropriate defoliation and debudding experiments indicate that exposure of mature leaves to short day in the absence of an actively growing bud on the plant (a) does not result in the produc...