Photocontrol of Plant Development by the Simultaneous Excitations of Two Interconvertible Pigments. III. Control of Seed Germination and Axis Elongation

Action spectra between 4100 and 8500 A for seed germination and radicle elongation were measured for Nemophila insignis and Lactuca sativa var. Great Lakes and between 6500 and 8500 A for seed germination of Lamium amplexicaule. The responses observed are features of the continued excitation of the photomorphogenic pigment in those regions of the spectra where both pigment forms have appreciable absorptivities.