Abstract
Supplementary radiation given at the beginning of the daily dark period exerts a marked influence on rate of stem elongation of green house-grown plants (Downs, et al., 1957). The influence of this radia tion is dependent on the ratio of red to far-red wave lengths in the radia tion. It is well known that the red/far-red ratio acts directly on the phytochrome pigment system. It may be supposed that the phyto chrome system exerts its effect through one or more stem growth factors. In the present paper it will be shown that some stem growth factor (presumably a hormone) produced in the young leaves and apex is responsible for the red/far-red sensitivity and necessary for normal internode elongation in Phaseolus seedlings.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
