PREFACE TO THE FIFTH RUSSIAN EDITION 



The main objective in preparing this volume has been to 

 present, in a brief and compact form, to the students of our 

 universities and agricultural colleges and to our future technical 

 agriculturists clear and exact information concerning the life 

 and vital functions of green plants. Such information should 

 help them to understand the significance of various methods that 

 are being applied in agricultural practice to increase the yield 

 and improve its quality. 



The ultimate purpose of the study of plant physiology is to 

 control the growth and development of the plant in order 

 to satisfy the need of mankind for plant materials as well as to 

 provide forage crops for livestock. Such control is possible only 

 on the basis of a fundamental study of the life of the plant as a 

 whole, as well as in its separate constituent processes. Analysis 

 of all the vital processes occurring in the plant is, therefore, a 

 very important part of physiology, and experimentation forms 

 the basic method for revealing the laws controlUng the vital 

 processes. But analysis should not obscure the synthetic 

 problems of plant physiology or the presentation of the whole 

 life of the plant as a united organism; on the contrary, they 

 should be intimately coordinated. 



The course in plant physiology in agricultural institutions 

 should differ from university courses both in its content and 

 in the form in which it is presented to the student. In such a 

 course, first place should be given to agricultural plants belonging 

 almost exclusively to the group of higher green plants. There- 

 fore, peculiarities of the physiology of saprophytes, parasites, 

 bacteria, fungi, and algae are scarcely dealt with in this book. 

 Many of these questions are discussed with sufficient detail in 

 textbooks of microbiology and phytopathology. A course in 

 plant physiology — or, as it is being termed of late, agrophysiology 

 — should include questions of special physiology of separate 

 groups of agricultural plants, as well as questions of varietal 

 physiology. Very often, differences in physiological properties, 

 apparently of no great significance, prove to be of value in 

 determining the usefulness of one variety or another for certain 

 economic and agricultural conditions. 



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