Author: Herman Augustus Spoehr

Publisher: Forgotten Books

Published: 2017-10-13

Total Pages: 90

ISBN-13: 9780265247310

Excerpt from The Carbohydrate Economy of Cacti The best evidence gained since the time of Sachs points to the conclusion that sugars are the first products which accumulate in the process of the photosynthesis of carbon compounds in the chlorophyllous cell. Thus, sugars may be considered the starting-point for the synthesis of the tre mendons number of substances found in living things, both vegetable and animal. What the sugar or mixture of sugars is which thus commands the center of attention in the metabolism of plants and of almost all living things is still a question of much dispute and uncertainty; nor does the solution of this problem seem possible until we have gained more knowledge of the transformations which the various sugars undergo in the cell, inde pendent Of photosynthesis. It has long been known that in the leaf, under circumstances, the polysaccharides are converted into the simpler sugars and vice versa, by what appears to be the shifting of an equilibrium by means of enzyme action. It is self-evident that a knowledge of these trans formations must be obtained before the problem of the first sugar syn thesized can be attacked. Not only in relation to the question of the immediate products of photo synthesis is the study of the carbohydrate equilibrium important, but also to the question of metabolism. In a very large number of plants, especially the higher ones, both the living and the lifeless matter consists in the main of material of carbohydrate nature. The lifeless matter forms the walls, vessels, supporting frame-work, and often a considerable amount of the reserve food-material. Those portions of the plant in which the manifesta tions of life appear, as for instance the chromatin of the nucleus and the protoplasm itself, contain a considerable quantity of carbohydrates, the life less being formed from the living and the living drawing upon the lifeless for support. It is, however, a question whether the difference between the living and lifeless is essentially one of chemical constitution. The idea that the living substance or protoplasm is a complex compound of more or less definite chemical constitution no longer seems tenable. Protoplasm, a mixture of so many different substances, undoubtedly varies in composition in different organisms. It is in all probability the study of the physical and chemical properties of protoplasm as a colloidal mixture (such proper ties as imbibition of water, electrical charges, and surface phenomena) which will yield the most illuminating results. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.