Kinetics and time dependence of the effect of far red light on the photoperiodic induction of flowering in Wintex barley

Journal Article · Sat Dec 01 04:00:00 EST 1979 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.64.6.1015· OSTI ID:5373862

Deitzer, G F; Hayes, R; Jabben, M

Flowering in the long day plant Hordeum vulgare L. var. Wintex barley was enhanced by the addition of far red light to the main light portion of the photoperiod. Far red energy was provided to produce quantum flux ratios (600/730 nm) and phytochrome photoequilibria (Pfr/total phytochrome) equivalent to those reported both beneath a leaf canopy and outside a canopy at twilight. The photoperiodic requirement for long days can be completely eliminated by the addition of far red light. However, both the effect of extending the photoperiod without far red and the addition of far red to 12-hour photoperiods were suboptimal. Maximal stimulation was achieved only when far red was added to continuous light. The duration of the period of maximal apex elongation rate, as well as the reduction of the time required for floral initiation, were saturated by three inductive cycles. When far red energy was provided intermittently during 3 days of continuous light, the ability to respond varied in a circadian manner. This enhancement of flowering by far red appears to be mediated by the high irradiance response of phytochrome.

• Research Organization: Radiation Biology Lab., Rockville, MD
• OSTI ID: 5373862
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 64:6; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
550200* -- Biochemistry
551000 -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
BARLEY
BIOLOGICAL EFFECTS
CEREALS
CHEMICAL REACTIONS
DAILY VARIATIONS
ELECTROMAGNETIC RADIATION
FLOWERS
GRAMINEAE
GRASS
GROWTH
PHOTOCHEMICAL REACTIONS
PHOTOPERIOD
PHYTOCHROMES
PIGMENTS
PLANTS
RADIATIONS
VARIATIONS
VISIBLE RADIATION