108 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1959 
Sciences Working Group on Orbiting Astronomical Observatories, 
National Aeronautics and Space Administration; and member of 
Physics of the Atmosphere and Space Committee, American Rocket 
Society. 
The Director is general editor of the Smithsonian Contributions 
to Astrophysics; and of the international publication Planetary and 
Space Physics. 
CHANGES IN STAFF 
Dr. John S. Rinehart accepted a professorship at the Colorado 
School of Mines, Golden, Colo. He left the Observatory during the 
summer of 1958. 
Dr. Gerhard F. Schilling resigned from the Observatory upon 
his appointment as Chief, Astronomy and Astrophysics, National 
Aeronautics and Space Administration, March 1959. 
Richard M. Adams, who had been on leave from Texas A. & M. 
College, resumed his duties there in June 1959. 
As of June 30, 1959, there were 179 persons employed at the 
Observatory. 
BUILDING AND EQUIPMENT 
The Astrophysical Observatory occupies space in five separate 
buildings. Plans for the erection of a new building on the grounds 
of the Harvard College Observatory have been approved; construc- 
tion is expected to begin during the fall of 1959. 
DIVISION OF RADIATION AND ORGANISMS 
The Division has been engaged in research into the biochemistry and 
biophysics of the photomorphogenic mechanism in plants as controlled 
by radiant energy. In general, the red portion of the spectrum induces 
growth reactions that can be nullified by subsequent exposure to the 
far-red part of the spectrum. 
Normal green sunflower seedlings produce large quantities of chlo- 
rophyll when grown in red or blue light, while, under the same condi- 
tions, mutant yellow or white seedlings lose their ability to synthesize 
protochlorophyll and chlorophyll. Although some chlorophyll is 
formed initially in these mutants, it is destroyed under continued 
exposure to light. Investigation of the photomorphogenic mechanism 
as measured by hypocotyl! inhibition indicated that the response was 
the same in yellow mutants and normal green seedlings, but 50 percent 
greater in the white mutants. The inference is that the yellow pig- 
ments may be active in a protective function. 
Studies are continuing on the biochemical changes that occur during 
the development of the chloroplasts of higher plants. It has been 
shown in our laboratory that excised leaves of dark-grown seedlings, 
when incubated on water and in the dark for 18 hours, lose one-half 
