The physiology of photosynthesis / by Sir Jagadis Chunder Bose.

  • Bose, Jagadis Chandra, 1858-1937.
Date:
1924
Catalogue details

Licence: In copyright

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

    34/316 (page 10)
    the lower solubility of nitrogen, the nitrogen and oxygen absorbed by water are as 2 : i. Table II.—Proportions of Gases present in 1000 c.c. of Pond V ater Specimen of water Nitrogen Oxygen Free and loosely held CO, Combined CO, Specimen I. II. . TIL . 12-88 c.c. 12-90 ,, 12-50 ,, 6-35 c.c. 6-13 ,, 5-47 - 3- 85 C.C. 4- m ,, 4•60 ,, 40-65 C.C. 40- 65 ,, 41- 4° - Average 12-79 c.c. 5-98 c.c. 4-00 C.C. 41 *oo c.c. The intercellular spaces of the plant are filled with nitrogen and oxygen dissolved in water, which are carried away with the oxygen evolved in photosynthesis. The gas given out in two different experiments was analysed and found to contain the following proportions of oxygen and nitrogen in 10 c.c. of evolved gas. First experiment . . . Oxygen, 4-29 c.c. ; Nitrogen, 5-71 c.c. Second experiment . . . Oxygen, 4-2 ,, ; Nitrogen, 5-8 ,, The proportion of oxygen to nitrogen was thus about 4 • 2 to 5-8. No carbon dioxide was found in the evolved gas ; the escape of C02 from its solution in water takes place only when the quantity of the gas in solution is excessive. Evolution of Pure Oxygen The first problem is to secure that the evolved gas shall be pure oxygen without any admixture of nitrogen, since the photosynthctic activity can only be accurately estimated by the rate of evolution of the pure gas. The difficulty has been met by placing the plant in a beaker filled with pond- water under the receiver of an air-pump. A partial vacuum is produced which removes the air contained in the plant and in the water ; this should be done slowly, for too sudden