[Low energy photocontrol of amaranthin formation in seedlings of Amarantus tricolor L. var. bicolor ruber Hort].

A grating monochromator has been used to study the effect of narrow wave-bands (5 nm) at a low energy level between 420 and 800 nm on the biosynthesis of amaranthin in Amarantus tricolor L. var. bicolor ruber Hort. seedlings. Besides a sharp peak in the red with a maximum at 660 nm, a narrow zone of activity in the blue has been detected (max. 440 nm).When seedlings cultivated on different substrates were sequentially exposed either to red (660 nm) and far red or to blue (440 nm) and far red, the second treatment, i.e. far red (730 or 735 nm), annihilated the effect of the first one, without having any influence on the chemical inductive treatments (kinetin or dihydroxy-3,4-phenylalanine).