Table of Contents 



INTRODUCTION 



George L. McNew The Broader Concepts of Plant Growth Regu- 

 lation 3 



William J. Robbins The Expanding Concepts of Plant Growth 



Regulation 13 



NATURALLY OCCURRING PLANT GROWTH SUBSTANCES 



Joyce A. Bentley Some Investigations on Interconvertible 



Naturally Occurring Auxins 25 



Poiil Larsen The Occurrence of Indole-3-acetaldehyde in 

 Torbj^rn Aasheim Certain Plant Extracts 43 



Donald G. Crosby New Auxins From 'Maryland Mammoth' To- 



A. J. Vlitos bacco 57 



C. H. Fawcett Chromatographic Investigations on the Meta- 



R. L. Wain holism of Certain Indole Acids and Their 



F. Wightman Amides, Nitriles, and Methyl Esters in Wheat 



and Pea Tissues 71 



P. F. Wareirig Growth Substance and Inhibitor Changes in 

 T. A. Villiers Buds and Seeds in Response to Chilling .... 95 



L. J. Audus On the Adaptation of Pea Roots to Auxins 

 /. K. Bakhsh and Auxin Homologues 109 



H. W. B. Barlow Some Biological Characteristics of an Inhibi- 



C. R. Hancock tor Extracted From Woody Shoots 127 



H. J. Lacey 



THE MECHANISMS OF AUXIN ACTIVATION 

 AND INACTIVATION 



P. L. Goldacre The Indole-3-acetic Acid Oxidase-Peroxidase 



of Peas 143 



E. R. Waygood Inhibition and Retardation of the Enzymati- 

 G. A. Maclachlan cally Catalyzed Oxidation of Indole-3-acetic 



Acid 149 



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