Reversible Photoreaction Controlling Expansion of Etiolated Bean-Leaf Disks

Effect of Radiation and Growth Regulators on Leaf Abscission in Seedling Cotton and Bean.

“…Also, red-light treatment caused the seedlings to be greener and more vigorous. This agrees with the promoting effect of red radiation on coleoptile sectioni elongation, and on the stem and leaf growth of etiolated seedlings (7,9,12,14 Downs (7), and Hendricks and Borthwick (9), an increasing list of light controlled responses have been found to be most effectively regulated by energy in the red region of the spectrum and are freely reversible by far-red radiation. All of the photomorphogenetic responses investigated to date appear to be controlled by a common basic mechanism (7).…”

“…The intake of water through dead root systems and its relation to the problem of absorption by transpiring plants. Amer (4,6,7,9,12,13,14,15). All of these processes have their maximum promotion in the red region of the spectrum at 6500 A and all are freely reversed by far-red radiation, the maximum effectiveness for reversal being attained at a wave length of about 7300 A.…”

Relationship Between Red Light Mediated Glyceraldehyde-3-Phosphate Dehydrogenase Formation and Light Dependent Development of Photosynthesis

“…Thus, the absorption of far-red light by Pr permits formation of sufficient quantities of the active form of the pigment, Pfr, to bring about the observed increase in enzyme level. Both leaf expansion (13) and increased ability to synthesize chlorophyll (19) have been shown to be controlled by the phytochrome system. The far-red light treatment used in these experiments brought about both of these responses, demonstrating further the conversion of Pr to Pfr during the 24-hour irradiation.…”

Photoreversibility of Flower Initiation.

“…This duodirectional reaction was shown to be repeatedly reversible and to be independent of temperature. This same reversible photoreaction was also established for the control of flower initiation of Xanthium (3), cuticle coloration of tomato fruits (20) and photomorphogenic effects such as leaf expansion (8,12), hypocotyl elongation (8) and the disappearance of the plumular hook of dark-grown beans (26).…”