Researches on plant respiration - III—The Relationship between the respiration in air and in nitrogen of certain seeds during germination (a) seeds in which fats constitute the chief food

Abstract

The relationship between aerobic and anærobic respiration has for some years been a subject which has interested plant physiologists, and as early as 1885 Pfeffer published values obtained in his laboratory for the ratios of the respiration intensities in hydrogen to those in air in the case of seedlings, fruits, and shoots of various species of plants. In 1913 Hill gave an account of investigations on respiration rates in air, nitrogen, and hydrogen using as his experimental material certain ripe and unripe fruits and also germinating wheat. The work of Flieg, published in 1922, is of a somewhat similar type to that here described; Flieg obtained the changes in the respiration rate, and also the changes in the respiratory quotient, of Aspergillus niger when cultures of this organism were successively kept in atmospheres of air, nitrogen, and again air. Boysen Jensen in 1923 described experiments similar to those of Hill but carried out with Aspergillus grown on prune extract, and also with leaves of Syringa vulgaris , Tropæolum majus , and seedlings of Sinapis alba ; in these experiments, however, hydrogen instead of nitrogen was used as the anærobic atmosphere. A critical series of investigations into the subject of the relative effects of air and nitrogen upon the respiration of apples has been described by Blackman and Parija in 1928. From an analysis of the results of these investigations Blackman has elaborated a theoretical scheme to explain the respiratory process in the light of his experimental data; to these papers we would refer our readers. The investigations described in the present paper, dealing with the respiration in air and in nitrogen of certain fat-storing seeds during germination were undertaken in order to see how far Blackman’s scheme can be applied to respiring tissue other than those he used. They were also carried out for the purpose of finally confirming the suitability of the katharometer method for work of this king; consequently with Helianthus annus and Ricinus communis duplicate sets of experiments were performed in which the respiration intensities, as indicated by carbon dioxide output, were measured by the Pettenkorer method and by the katharometer respectively. It will be seen from the results of these experiments that the katharometer method is very suitable for such work, and, in fact, possesses a number of distinct advantages over the older method.