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AGRICULTURAL AND BIOLOGICAL PUBLICATIONS
CHARLES V. PIPER, CONSULTING EDITOR
THE CHEMISTRY OF PLANT LIFE
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THE CHEMISTRY OF PLANT LIFE
BY
ROSCOE W. THATCHER, M.A., D.AGR.
DEAN OF THE DEPARTMENT OF AGRICULTURE
AND DIRECTOR OF THE AGRICULTURAL EXPERIMENT STATIONS.
UNIVERSITY OF MINNESOTA
(FORMERLY PROFESSOR OF PLANT CHEMISTRY. UNIVERSITY OF MINNESOTA)
FIRST EDITION
SECOND IMPRESSION
MCGRAW-HILL BOOK COMPANY, INC.
NEW YORK: 370 SEVENTH AVENUE
LONDON: 6 & 8 BOUVERIE ST., E. C. 4
1921
COPYRIGHT 1921; BY THE McGRAW-HILL BOOK COMPANY, INC.
PREFACE
The author has had in mind a two-fold purpose in the preparation of this
book. First, it is hoped that it may serve as a text or reference book for
collegiate students of plant science who are seeking a proper foundation
upon which to build a scientific knowledge of how plants grow. The late
Dr. Charles E. Bessey, to whom I owe the beginning of my interest in plant
life, once said to me: "The trouble with our present knowledge of plant
science is that we have had very few chemists who knew any botany, and no
botanists who knew any chemistry." This may have been a slightly
exaggerated statement, even when it was made, several years ago. But it
indicated a very clear recognition by this eminent student of plants of the
need for a better knowledge of the chemistry of plant cell activities as a
proper foundation for a satisfactory knowledge of the course and results of
plant protoplasmic activities. It is hoped that the present work may
contribute something toward this desired end.
Second, the purpose of the writer will not have been fully accomplished
unless the book shall serve also as a stimulus to further study in a
fascinating field. Even the most casual perusal of many of its chapters
cannot fail to make clear how incomplete is our present knowledge of the
chemical changes by which the plant cell performs many of the processes
which result in the production of so many substances which are vital to the
comfort and pleasure of human life. Studies of the chemistry of animal life
have resulted in many discoveries of utmost importance to human life and
health. It requires no great stretch of the imagination to conceive that
similar studies of plant life might result in similar or even greater
benefit to human life, or society, since it is upon the results of plant
growth that we are dependent for most of our food, clothing, and fuel, as
well as for many of the luxuries of life.
The material presented in the book has been developed from a series of
lecture-notes which was used in connection with a course in
"Phyto-chemistry" which was offered for several years to the students of
the Plant Science Group of the University of Minnesota. In the preparation
of these notes, extensive use was made of the material presented in such
general reference works as Abderhalden's "Biochemische Handlexicon" and
"Handbuch der Biochemischen Arbeitsmethoden," Oppenheimer's "Handbuch der
Biochemie des Menschen und der Tiere," Czapek's "Biochemie der Pflanzen,"
Rohmann's "Biochemie," Frankel's "Descriptive Biochemie," and "Dynamische
Biochemie," Euler's "Pflanzenchemie," and Haas and Hill's "Chemistry of
Plant Products"; as well as of the most excellent series of "Monographs on
Biochemistry," edited by Plimmer, several numbers of which appeared in
print prior to and during the period covered by the preparation of these
lectures. Frequent use was made also of the many special treatises on
individual groups of compounds which are mentioned in the lists of
references appended to each chapter, as well as of articles which appeared
from time to time in various scientific journals.
Hence, no claim is made of originality for the statements presented herein,
except in an insignificant number of studies of enzyme action, and of the
possible physiological functions of certain specific compounds. The only
contributions which the writer has felt qualified to make to this general
subject are those of an intense personal interest in the chemistry of plant
processes and a viewpoint with reference to the relation of chemical
processes to vital phenomena which will be apparent as the various subjects
are presented.
The text has been prepared upon the assumption that the students who will
use it will have had some previous training in elementary inorganic and
organic chemistry. A systematic laboratory course in organic preparations,
such as is required of students who are preparing to become professional
chemists, is not at all a necessary requisite to the understanding of the
chemistry of the different groups of plant compounds as here presented; but
it is assumed that the student will have had such previous training as is
now commonly given in a one-year collegiate course in "General Chemistry,"
or a year's work in general inorganic chemistry followed by a brief course
in "Types of Carbon Compounds" or "Elements of Organic Chemistry," such as
is usually required of students who are preparing for advanced work in
agricultural science, in animal or human nutrition, etc.
An attempt has been made to arrange the material in such a way as to
proceed from simpler chemical principles and substances to those of more
complex structures. This results in an arrangement of the groups to be
studied in an order which is quite different than their biological
significance might suggest. It is believed, however, that in the end a more
systematic understanding and a more orderly procedure is obtained in this
way than would result from the treatment of the groups in the order of
their relative biological importance.
CONTENTS
INTRODUCTION PAGE
Development of biological science; characteristics of protoplasm;
plant and animal life, similarities and differences; protoplasmic
activity essentially chemical changes; objects of study of the
chemistry of plant life xiii-xvi
CHAPTER I--PLANT NUTRIENTS
Definitions; the plant food elements; available and unavailable
forms; the value of the different soil elements as plant foods;
functions of the different plant food elements in plant growth;
inorganic plant toxins and stimulants; references 1-15