. Biological effects of radiation; mechanism and measurement of radiation, applications in biology, photochemical reactions, effects of radiant energy on organisms and organic products. Radiation; Biology. 844 BIOLOGICAL EFFECTS OF RADIATION be able to carry on limited photosynthesis when placed under infra-red at night. This test was made recently as follows: Four pots of buckwheat seedlings were grown in a greenhouse during the months of December and January under solar illumination during the day and under the infra-red from a 500-watt lamp each night. A composite filter made up of Coming's
. Biological effects of radiation; mechanism and measurement of radiation, applications in biology, photochemical reactions, effects of radiant energy on organisms and organic products. Radiation; Biology. 844 BIOLOGICAL EFFECTS OF RADIATION be able to carry on limited photosynthesis when placed under infra-red at night. This test was made recently as follows: Four pots of buckwheat seedlings were grown in a greenhouse during the months of December and January under solar illumination during the day and under the infra-red from a 500-watt lamp each night. A composite filter made up of Coming's heat-transmitting glass 4 mm. in thickness was used to remove the visible region. The transmission of this glass has been indicated in a previous publication (1). The filter was supported on a wooden stand a short distance below the lamp. The distance from the lamp to the soil in which the seedlings were grown was 22 in. The lamp was fitted with an aluminum reflector for directing. Fig. 1.—Buckwheat seedlings. D, at left, grown in darkness. , at right, received only the infra-red of sunlight. Note that there is no difTerence in the appearance of the two. The green pigment chlorophyll does not develop under infra-red. the radiation downward so as to cover the filter effectively. A second set of four plants was grown beside the first set and was treated similarly except that a sheet of galvanized iron was used under the second lamp instead of the infra-red filter. The seedlings were grown for two weeks, then were cut down and green and dry weights determined. This test was repeated during January and February, In each test the seedlings were grown from seed for approximately two weeks before they were placed under the test conditions. The results are shown in Table 2. The seedlings in the first test were grown during a period of cloudy weather and produced much less dry weight than those in the second test. There is no evidence, however, that those grown under infra-red ea
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