Effect of Ultraviolet Radiation, White Light, and Cytokinin Phytoregulators on biosynthesis of Amaranthine and Photosynthetic Pigments in Amaranth Seedlings

摘要

The effect of long-wavelength UV radiation (UV-A) with a spectral maximum at 353 nm and natural illumination on the growth processes and biosynthesis of amarathine, chlocophylls, and carotenoids was studied in seminal leaves of five-day-old seedlings of amaranth (Amaranthus cruentus L., cultivar Tampola) grown in the presence of 10~(-6) or 10~(-4) M 6-benzylaminopurine (BAP), thidiazurone, and metribuzine, Within the concentration range studied, both BAP and thidiazurone caused an increase in the amaranthine content, a 1.5- to 3-fold decrease in root length, and a four- to sevenfold decrease in the hypocotyl length of the plants grown in the dark relative to control plants treated with water and grown under otherwise identical conditions. The stimulatory effect of UV-A radiation and natural white light on the biosynthesis of amaranthine and photosynthetic pigments depended on the chemical structure of synthetic phytoregulators and on their concentration. The three cytokinin phytoregulators studied were shown to promote the stimulatory effects of both UV-A radiation and natural white light, although the extents of stimulation were different. Only BAP and thidiazurone stimulated dark reactions of amaranthine biosynthesis, whereas metribuzine stimulated only the light-induced reactions of biosynthesis of this pigment.