Studies on the regulation of Chrysanthemum flowering with special reference to plant regulators

Almost the same budding response as in the inductive treatments of entire, fully foliated plant was obtained only if the upper 5 to 7 expanded leaves, adjacent to the apex, were given short day treatments. Even a single just-expanded leaf was sufficient to produce the macroscopically visible bud though with some delay.The localized photoperiodic treatments of SD/LD or LD/SD in the case of two leaves in the upper portion indicated that LD leaves inhibited the action of SD leaves, ability to induce flower formation at the apex and to stimulate growth. Increasing the number of LD leaves situated between the apex and 8 SD leaves, if they were mature ones, did not prevent the bud appearance, but only delayed. Stem elongation decreased inversely with increasing the number of LD leaves.Inhibiting action of LD leaves may be attributable to decreasing activity of floral stimulus at the apex.