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Photoreactions in Phycomyces : Responses to the stimulation of narrow test areas with ultraviolet light
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 re...
Autores principales: | , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
1961
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2195141/ https://www.ncbi.nlm.nih.gov/pubmed/13721531 |
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author | Delbrück, M. Varjú, D. |
author_facet | Delbrück, M. Varjú, D. |
author_sort | Delbrück, M. |
collection | PubMed |
description | 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. |
format | Text |
id | pubmed-2195141 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1961 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21951412008-04-23 Photoreactions in Phycomyces : Responses to the stimulation of narrow test areas with ultraviolet light Delbrück, M. Varjú, D. J Gen Physiol Article 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. The Rockefeller University Press 1961-07-01 /pmc/articles/PMC2195141/ /pubmed/13721531 Text en Copyright © Copyright, 1961, by The Rockefeller Institute This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Article Delbrück, M. Varjú, D. Photoreactions in Phycomyces : Responses to the stimulation of narrow test areas with ultraviolet light |
title | Photoreactions in Phycomyces
: Responses to the stimulation of narrow test areas with ultraviolet light |
title_full | Photoreactions in Phycomyces
: Responses to the stimulation of narrow test areas with ultraviolet light |
title_fullStr | Photoreactions in Phycomyces
: Responses to the stimulation of narrow test areas with ultraviolet light |
title_full_unstemmed | Photoreactions in Phycomyces
: Responses to the stimulation of narrow test areas with ultraviolet light |
title_short | Photoreactions in Phycomyces
: Responses to the stimulation of narrow test areas with ultraviolet light |
title_sort | photoreactions in phycomyces
: responses to the stimulation of narrow test areas with ultraviolet light |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2195141/ https://www.ncbi.nlm.nih.gov/pubmed/13721531 |
work_keys_str_mv | AT delbruckm photoreactionsinphycomycesresponsestothestimulationofnarrowtestareaswithultravioletlight AT varjud photoreactionsinphycomycesresponsestothestimulationofnarrowtestareaswithultravioletlight |