PREFACE XI 



Many of the books and reviews are at least as broad as the present 

 volume and could be used as references in virtually all sections. The 

 interested reader who wants to see original papers can find references 

 according to topic in nearly any of these recent books or reviews 

 (see especially 3, 9, 11, 14, 20, 21, 22, 25, 26, 28, or 32). Actually, 

 nearly all work not directly cited in this book is documented 

 in my own review (32). The printed report of the recent symposium 

 in Australia will contain very recent references, and I am indebted 

 to Dr. Erwin Biinning for showing me some of these manuscripts. 

 My last revision was strongly influenced by them. 



In spite of this approach to literature citation through reviews, it 

 was felt that more direct reference should be made in cases where 

 work (rather than well-known conclusions) is specifically mentioned, 

 using the name and location of the investigator. In these cases a 

 recent pertinent paper is cited. Figures copied from published papers 

 are also acknowledged in the figure captions, giving further specific 

 references. Table 7-1 contains references to a number of papers 

 which are either quite recent or not easily found in the reviews. There 

 is also a considerable amount of unpublished work which is discussed 

 in the book. Usually this is apparent from the figure headings. 



The manuscript was used in an early duplicated draft in an 

 advanced plant physiology class at Colorado State University during 

 the spring of 1962. As a result of discussions in this class, many of 

 the ideas now incorporated into the text developed, and a number of 

 experiments were performed. Thus I am indebted for both intellectual 

 and material help to the members of this class: Charles Curtis, Lee 

 Eddleman, Nagah Karamani El Sayed, James Gary Holway, 

 Deogratias Lwehabura, Oscur Schmunk, and James Whitmore. 



After arriving in Tubingen (in August, 1962, for a sabbatical year), 

 the manuscript was almost completely rewritten. Drs. Arthur 

 Galston, Anton Lang, Jan Zeevaart, and Phillip Wareing had read 

 the duplicated version, and their comments contributed much to the 

 rewriting. Drs. Erwin Biinning and Lars Lorcher also read parts of 

 the manuscript and made valuable suggestions. During the rewriting, 

 Drs. Galston and Wareing supplied immeasurable help by reading 

 and commenting on the Tubingen version. I am also deeply indebted 

 to my assistant, Jean Livingston, and my graduate student Carol 

 Pollard, who answered my many mailed requests to Colorado, 

 sometimes by performing experiments to answer questions that kept 



