Experimental researches on photoperiodism (3) : Some relationships between the localized high temperature and the flower formation.

Abstract

1. The seedilngs of the Japanese morning glory, Pharbitis Nil known as one of the most sensitive short day palnts were used as a material. The effects of a localized warming of the single leaf, petiole, stem, and terminal bud on flower formation were studied in order to find out if the principal effects of high temperature were upon the induction within the leaf, transolocation of the stimulus for flower initiation from leaf to meristems, or on morphogenous reactions at the apical meristem. 2. When a single leaf was given high temperature at 36℃ during the dark period of 16 hours, flower formation did not occure. 3. When petiol, stem and terminal bud were continouously given high temperature at 36℃, also no flower formation occured. 4. When petiol, stem, and terminal bud were treated with high temperature at 36℃ during 16 hour dark period, greatest flower inhibition occured in the terminal bud, but slight flower inhibition in other lots. 5. The 1st node of flower bud in the lots of high temperature usually rose slightly higher than one in control. 6. Significant differece in stem elongation rate during the high temperature treatment could not be observed except that of stem elongation in the lot of single leaf high temperature which was promoted more than control.