The physiology of photosynthesis / by Sir Jagadis Chunder Bose.

  • Jagadish Chandra Bose
Date:
1924
Catalogue details

Licence: In copyright

Credit: The physiology of photosynthesis / by Sir Jagadis Chunder Bose. Source: Wellcome Collection.

    235/316 page 211
    SIMULTANEOUS DETERMINATION OF CARBOHYDRATE- FORMATION BY TWO INDEPENDENT METHODS Diicct and indirect estimation of photosynthetic production of carbo- hydrate—Indirect methods based on absorption of carbon dioxide and on evolution of oxygen—Oxygen-carbohydrate factor—Indirect deter- mination of increase of weight from volume of evolved oxygen Direct determination by weighing the plant before and after exposure to light—Simultaneous determination of carbohydrate by direct and indirect methods'—The Eudiometer and the Balance—Modification of the carbohydrate-factor by external conditions—Effect of strong light and of semi-darkness. In the last chapter the method of direct estimation of the photosynthetic product by weighing was explained and shown to give consistent results. The experimental methods and conditions were shown to be such as to eliminate many possible sources of error. The question now arises whether it is at all possible to devise an inde- pendent method for determining the increase of weight. Success in this would enable us to compare the results obtained by the two methods, the mutual agreement of which would offer a conclusive test of the reliability of each. Such a method is to be found in the accurate determination of the volume of oxygen evolved during photosynthesis. It will also be shown that, in normal specimens of Hy dr ilia growing in a tank exposed to northern light from the sky and not to direct sunlight, the ratio of the increase of weight under light to the weight of oxygen evolved during the same exposure is remarkably constant. The increase of weight in normal plants may, therefore, be estimated by multiply- ing the weight of oxygen by the constant oxygen-carbo- hydrate factor. The method of determining the increase of weight
    No text description is available for this image
    No text description is available for this image
    No text description is available for this image