CONTENTS 



Page 



Foreword v 



Preface vii 



Preface to the German Edition ix 



CHAPTER I 



Introduction and Historical Sketch 1 



Growth and growth substances 1 



Historical sketch 5 



Darwin — Wiesner — Rothert — Fitting — Boysen Jensen — Paal — 

 Stark and Drechsel — Formulation of the growth-substance 

 explanation. 

 Summary 15 



CHAPTER II 

 Detection and Quantitative Determination of Growth Sub- 

 stances 16 



The test for the presence of growth substances with the Avena 



coleoptile 16 



The culture of the Avena seedling for use as a phytohormone test 

 object — Culture conditions — Culture methods — Preparation of the 

 Avena coleoptile for use — Decapitation and unilateral application — 

 Growth curs'ature of the coleoptile — Preparation of the material to 

 be tested — Direct application of plant parts to the decapitated 

 Avena coleoptile^Application of material to be tested in agar and 

 in lanolin — Detection of growth substance in fluids — Detection of 

 growth substance in pollen — Diffusion of growth substance into 

 agar — Diffusion of growth substance into dextrose-agar — Diffusion 

 of growth substance into water — Extraction of growth substance 

 with alcohol — Extraction of growth substance with chloroform — 

 Extraction of growth substance with water. 



Quantitative determination of growth substances 27 



Determination of growth curvature produced by the unilateral 

 action of a growth substance — Boysen Jensen's quantitative 

 method — Went's quantitative method — Comparison of the units of 

 different workers — Other quantitative methods — Growth in 

 length of decapitated coleoptiles — Pea test method — Callus- 

 forming effect of growth-substance pastes — Comparison of Avena 

 with other test objects. 



Summary 38 



xi 



47664 



