SECRETARY'S REPORT 81 



Witheow, R. B., and Moh, C. C. Nonionizing radiant energy as an agent in 

 altering the incidence of X-ray-induced chromatid aberrations. I, Effects 

 of far-red and infrared radiant energy on Tradescantia and Vicia. Radiation 

 Res., vol. 6, pp. 491-500, 1957. 



Withkow, R. B., and Price, L. A darkroom safelight for research in plant 

 physiology. Plant Physiol., vol. 32, pp. 244-248, 1957. 



Withrow, R. B., and Withrow, Alice P. Generation, control and measurement 

 of visible and near-visible radiant energy. In "Radiation Biology," vol. 3, 

 pp. 125-259. McGraw-Hill Book Co., 1956. 



OTHER activities 



Papers on the research in progress were presented during the past 

 year at several international and national science meetings. At the 

 annual meeting of the American Society of Plant Physiologists at 

 Storrs, Conn., the following papers were given : 



Elimination of the lag phase of chlorophyll synthesis in dark-grown bean leaves 



by a pretreatment with low irradiances of monochromatic energy, by R. B. 



Withrow, J. B. Wolff, and L. Price. 

 The action spectrum and kinetics of far-red blocking of the red-induced opening 



of the hypocotyl hook of bean, by W. H. Klein, R. B. Withrow, and V. Elstad. 

 The role of chlorophyllase in the synthesis of chlorophyll a in higher plants, by 



J. B. Wolff and L. Price. 



At a meeting of the Southern Section of the American Society of 

 Plant Physiologists at Birmingham, Ala., R. B. Withrow gave a paper 

 entitled "Action Spectrum and Photomorphogenesis in Higher 

 Plants," and at the Midwest Section at Ann Arbor, Mich., W. H. Klein 

 participated in a round-table discussion on "Effects of Light Quality 

 on Plant Development." At the International Photobiology Con- 

 ference at Turin, Italy, and the International Photoperiodism Con- 

 gress at Parma, Italy, R. B. Withrow discussed the current research 

 of the laboratory. R. B. Withrow and Walter Shropshire attended 

 the national organizational meeting of the Biophysical Society held 

 at Columbus, Ohio. 



During the year, R. B. Withrow served as consultant to the Office 

 of the Commanding General, U. S. Air Forces in Europe, and also as 

 consultant to the Argonne National Laboratory. He was appointed 

 chairman of the International Symposium on Photoperiodism in 

 Plants and Animals, sponsored by the National Research Council, 

 which is to be held at Gatlinburg, Tenn., in the fall of 1957. 



Respectfully submitted. 



F. L. Whipple, Director. 



Dr. Leonard Carmichael, 

 Secretary, Smithsonian Institution. 



