GROWTH AND NUTRIENT RESPONSES OF LITTLE TURKISH TOBACCO TO LONG AND SHORT PHOTOPERIODS

Physiological studies of strongly photoperiodic species in long and short day have hitherto dealt predominantly with the effect of day length upon development rather than upon growth. In photoperiodic species which flower in only one of two contrasted day lengths, it becomes difficult to compare or interpret data on growth due to simultaneous developmental differences of plants grown in unlike photoperiods. The use of so-called dayneutral species whose flowering response is relatively independent of day length facilitates recognition of growth as opposed to developmental responses caused by the photoperiod. Though data are available on the photoperiodic responses of certain day-neutral forms such as the tomato, it nevertheless seemed worthwhile to undertake a study of growth responses of a species having a distinctly different structural habit from those types studied heretofore.