Influence of Temperature on Photoperiodic Reactions in Leaf Blades of Biloxi Soybean

1. Apparatus was devised that made possible the application of controlled temperature to individual leaves of Biloxi soybean plants during the dark periods of a photoperiodic treatment, while the remainder of the plant received greenhouse temperatures and long photoperiods. 2. When a leaf was held at 50⚬F. or lower during a 5-day induction period, floral initiation was greatly inhibited. At 70⚬-90⚬, such initiation was in general equal to that of the controls held at greenhouse temperatures, but at 90⚬ or higher the extent of the initiation again was less. 3. On the basis of the data presented in this and two preceding papers, the inhibiting effect of low temperature on floral initiation in Biloxi soybean plants appears to be the result of its effect on the photoperiodic reactions occurring in the leaf blade during the dark period, rather than through its effect on translocation of a flower-inducing stimulus from the leaf to the terminal meristems or its effect at the terminal meristems upon the different...