You are not currently logged in.
Access your personal account or get JSTOR access through your library or other institution:
In-vitro Binding of Phytochrome to a Particulate Fraction: A Function of Light Dose and Steady-state P fr Level
Peter H. Quail
Vol. 118, No. 4 (1974), pp. 357-360
Published by: Springer
Stable URL: http://www.jstor.org/stable/23371046
Page Count: 4
Preview not available
The binding of phytochrome to a particulate fraction in extracts from hypocotyl hooks of etiolated Cucurbita pepo L. seedlings has been examined as a function of the light dose and Pfr level established in vitro. As the steady-state level of Pfr transiently established in the 500 × g supernatant is increased, so the level of Pr subsequently pelletable at 20000 × g increases up to a saturation level. Increasing both the time and irradiance parameters of the light dose while holding the steady-state Pfr level constant, results similarly in increasing Pr pelletability. This agrees with results obtained previously with in-vivo irradiations of maize coleoptiles. Thus, like the in-vivo response, phytochrome binding in vitro appears to be a function of the total number of molecules converted to the Pfr form during the irradiation period.
Planta © 1974 Springer