Antagonistic but complementary actions of phytochromes A and B allow optimum seedling De-etiolation

Journal Article · Sun Jun 01 04:00:00 EDT 1997 · Plant Physiology (Bethesda)

DOI:https://doi.org/10.1104/pp.114.2.637· OSTI ID:577268

Smith, H ^[1]; Xu, Yong ^[2]; Quail, P H ^[2]

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1. Univ. of Leicester (United Kingdom)
2. Plant Gene Expression Center, Albany, CA (United States)

Using dichromatic radiation, we show that the actions of phytochromes A and B (phyA and phyB) in Arabidopsis thaliana are antagonistic in mediating red and far-red radiation effects on seedling de-etiolation and yet act in a complementary manner to regulate de-etiolation, irrespective of spectral composition. At low phytochrome photoequilibria inhibition of hypocotyl extension was strong, because of the action of a far-red high-irradiance response mediated by phyA. At high phytochrome photoequilibria inhibition of hypocotyl extension was also strong, because of the action of phyB. At intermediate photoequilibria hypocotyl inhibition was less strong. In their natural environment, this dual action will strongly retard hypocotyl growth and promote cotyledon opening and expansion both in open daylight and under dense vegetation. Overlapping action by phyA and phyB will substantially promote de-etiolation in sparse vegetation. The antagonistic and complementary actions of phyA and phyB, therefore, allow the optimum regulation of seedling growth after emergence from the soil.

• OSTI ID: 577268
• Journal Information: Plant Physiology (Bethesda), Journal Name: Plant Physiology (Bethesda) Journal Issue: 2 Vol. 114; ISSN PLPHAY; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
ARABIDOPSIS
FAR INFRARED RADIATION
INHIBITION
PHYTOCHROMES
PLANT GROWTH
RADIATION EFFECTS