The growth and the efficiency (E s ) of conversion of solar energy were greatly affected in barley by both shading and density, although not always similarly in 1957 and 1958. Observations were made on: height; internode length; shoot diameter; shoot and leaf number; number and percentage of dead leaves; leaf length, breadth, ratio, thickness and a...
Light of various spectral regions (at low or high intensities) supplemented a short day (SD) in white light, or was used alone at high intensity. Two types of relation of wave length to photoperiodic reaction were found: Crucifers were sensitive to blue and infrared (even SD exposure promoted elongation and flowering) and did not respond to 520-700...
Flowering of the SD plant Perilla crispa was also possible in LD and in continuous light, if lighting was weak enough. The light range within which flowering is possible, decreased with increasing day length. With an illumination of 300μwatts/cm 2spherical cross-section, seedlings were day-neutral. Older plants proved more predisposed to flower tha...
