CHAPTER 7 



Chlorophyll Formation and Accumulation in Plants 



James H. C. Smith and Violet M. K. Young 



Department of Plant Biology, Carnegie Institution of Washington, 



Stanford, California 



Description of the naturally occurring process. Precursors of chlorophyll. Properties 

 of protochlorophyll: Chemical nature of protochlorophyll — Physical properties of proto- 

 chlorophyll — Physiological properties of protochlorophyll. Effect of temperature on 

 chlorophyll formation and accumulation. Influence of the ambient atmosphere on the 

 formation and accumulation of chlorophyll . Influence of nutrition on the formation and 

 accimiulation of chlorophyll. Chlorophyll formation in the dark. Use of chlorophyll 

 mutants. Mechanism of chlorophyll biosynthesis. References. 



In photosynthetic organisms, seven types of chlorophyll have been 

 identified: chlorophylls a, b, c, d, and e, bacteriochlorophyll, and bac- 

 terioviridin. The distribution of these pigments has been summarized 

 by Strain (1949, 1951). Chlorophyll a is the most widely distributed of 

 these pigments. It is "common to all autotrophic organisms except the 

 pigmented bacteria" (Strain, 1949); chlorophyll b accompanies chloro- 

 phyll a in the higher plants and in some algae; and chlorophylls c, d, 

 and e appear only in algae and associated with chlorophyll a. Bacterio- 

 chlorophyll is the chlorophyll of a number of strains of purple and brown 

 bacteria (Van Niel and Arnold, 1938), and bacterioviridin, of the green 

 bacteria (Metzner, 1922; cf. French and Young, Chap. 6, this volume). 



Unfortunately the biosynthesis of only chlorophylls a and b has been 

 studied in detail. Of necessity, therefore, this article will be devoted 

 solely to a review of the development of these chlorophylls. Although 

 these chlorophylls are found in organs other than the chief photosyn- 

 thetic organs of plants, for example, in stems, flowers, seeds, roots, and 

 tubers, space will not permit a discussion of the chlorophyll-forming proc- 

 ess in these organs. For information regarding this aspect of the subject, 

 the reader is referred to articles by Lubimenko (1926) and by Larsen 

 (1949, 1950). 



As an introduction to the analysis of the process of chlorophyll for- 

 mation and accumulation, we will first describe the naturally occurring 

 process in the higher plants. 



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