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Photoreactions in Phycomyces. Responses to the stimulation of narrow test areas with ultraviolet light

Delbrück, M. and Varjú, D. (1961) Photoreactions in Phycomyces. Responses to the stimulation of narrow test areas with ultraviolet light. Journal of General Physiology, 44 (6). pp. 1177-1188. ISSN 0022-1295. http://resolver.caltech.edu/CaltechAUTHORS:DELjgp61

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Abstract

Equipment has been developed for ultraviolet illumination of sharply bounded test areas of the growing zone of sporangiophores of Phycomyces. The growing zone is opaque for this light and the tropic responses are negative. Periodic short narrow stimuli on alternating sides produce periodic tropic responses when applied at x > 0.5 mm, but none for x < 0.5 mm, where x is the distance below the sporangium. Sustained tropic stimuli, applied at constant x, produce tropic responses for any x > 0.1 mm. The lag between stimulus and response is 3.3 min. for any x > 0.5 mm. For smaller x the lag increases progressively. In all cases the tropic bend occurs at values of x > 0.5 mm. Sustained tropic stimuli, applied at constant height relative to ground, produce relatively sharp tropic bends. The center of the bend is at all times close to the simultaneous position of the stimulated area. The boundaries of a light-adapted zone move less than 0.1 mm in 10 min. relative to the sporangium. It is concluded that the receiving and adapting structures do not move relative to the sporangium, and that the responding system does not move relative to ground. The two systems move relative to each other with the speed of growth. The responding system does not extend above x = 0.5 mm.


Item Type:Article
Additional Information:Copyright © 1961 by The Rockefeller University Press. RUP grants the public the non-exclusive right to copy, distribute, or display the Work under a Creative Commons Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ and http://creativecommons.org/licenses/by-nc-sa/3.0/legalcode. Received for publication, December 16, 1960. The authors are indebted to Mrs. Lois Edgar, Mr. A. Bacher, and Mr. P. Gaff for technical assistance. This work was supported by a grant from the National Science Foundation.
Record Number:CaltechAUTHORS:DELjgp61
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:DELjgp61
Alternative URL:http://www.jgp.org/cgi/content/abstract/44/6/1177
Usage Policy:RUP grants the public the non-exclusive right to copy, distribute, or display the Work under a Creative Commons Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ and http://creativecommons.org/licenses/by-nc-sa/3.0/legalcode.
ID Code:10846
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:13 Jun 2008
Last Modified:26 Dec 2012 10:05

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