I 







CONTENTS 



Preface page ix 



List of Plates xi 



Chapter I. Historical Introduction 1 



II. Methods of Investigating Micro- 

 Nutrient Problems 21 



1. The Purification of Materials used in 

 Culture Experiments 21 



2. The Estimation of Micro-nutrient Ele- 

 ments in Plant Material 26 



3. The Diagnosis of Mineral Deficiencies of 

 Plants 51 



III. Trace-Element Deficiency Diseases of 



Plants 57 



1. Diseases Attributable to a Deficiency of 

 Manganese 57 



2. Diseases Attributable to a Deficiency of 



Zinc 68 



3. Diseases Attributable to a Deficiency of 

 Boron % 80 



4. Diseases Attributable to a Deficiency of 

 Copper 90 



5. The Symptoms of Molybdenum Deficiency 96 



IV. The Functions of Trace Elements in 



Plants 97 



60980 



