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LIBRARY 



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PREFACE 



This book has developed largely from the courses in plant physiology as 

 taught by the authors at the Ohio State University and the University of 

 North Carolina. The authors have attempted to organize a discussion of the 

 fundamental facts and principles of this subject which can be included be- 

 tween the covers of a volume of moderate dimensions. It is believed that 

 this book can be readily adapted to use with any introductory course in plant 

 physiology based upon prerequisites of general botany and general chemistr>\ 

 The introductory course in plant physiology at the Ohio State University 

 differs considerably from that at the University of North Carolina. In the 

 former institution, for example, it is a two-quarter course; in the latter 

 a one-quarter course. Nevertheless the authors expect to use this book suc- 

 cessfully in both these courses. Although the discussion is necessarily concise 

 the subject has been treated comprehensively, and it is believed that few if any 

 topics which would be considered significant by the majority of plant physi- 

 ologists have been neglected. 



This text can be used as the basis for a conventional recitation course, or 

 as a background source of information for student reading in connection with 

 lecture-discussion courses. There is a continuity of presentation from chapter 

 to chapter which especially adapts the book to such a usage. If only certain 

 topics are selected for laboratory or lecture consideration, reading of the in- 

 tervening chapters should help the student to fit the classroom work into a 

 coordinated picture of the science as a whole. 



We have attempted throughout the text to bring into bold relief the 

 fundamental principles of plant physiology rather than to present only an 

 encyclopedic compilation of undigested and sometimes contradictory facts. 

 Most of the discussion is based directly on data selected from the original 

 literature much of which is presented in tabular or graphical form. A 

 consistent attempt has been made to keep the discussion abreast of modern 

 developments in plant physiology without neglecting concepts which have 

 stood the test of time. 



Nowadays it is scarcely less than axiomatic that any discussion of physi- 

 ology must be grounded on the principles of physics and chemistry. Further- 

 more, the student must have a clear concept of the physical nature of the 



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