CONTENTS 



Section I Photochemical Principles 



Reversible Photochemical Properties of Dyes, by Gerald Oster 3 



Action Spectra and Optical Properties of Cellular Pigments, 



by C. S. French 15 



Remarks on the Significance of Action Spectra, by Frederick 

 S. Brackett and Alexander Hollaender 41 



Energy Transfer in Ordered and Unordered Photochemical 

 Systems, by Gordon Tollin, Power B. Sogo, and Melvin 

 Calvin 47 



Section II Photocontrol of Seed Germination and 

 Vegetative Growth by Red Light 



Photoperiodism in Seeds and Buds, by P. F. W arcing 73 



Effect of Light on the Germination of Seeds, by E. H. Toole 89 



Photomorphogenesis in Different Spectral Regions, by 



G. Meijer 101 



Some Effects of High-Intensity Irradiation of Narrow Spectral 

 Regions, by E. L. Wassink, P. J. A. L. de Lint, and J. Ben- 

 sink 111 



Photocontrol of Vegetative Growth, by R. J. Downs 129 



Studies on Indoleacetic Acid Oxidase Inhibitor and Its Re- 

 lation to Photomorphogenesis, by Arthur W. Galston 137 



Section III Role of Chemical Agents in Photocontrol 

 of Vegetative Growth 



Control of Leaf Growth by an Interaction of Chemicals and 



Light, by James L. Liver man 161 



xui 





