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Enhancement of phototropic response to a range of light doses in Triticum aestivum coleoptiles in clinostat-simulated microgravityThe phototropic dose-response relationship has been determined for Triticum aestivum cv. Broom coleoptiles growing on a purpose-built clinostat apparatus providing gravity compensation by rotation about a horizontal axis at 2 rev min-1. These data are compared with data sets obtained with the clinostat axis vertical and stationary, as a 1 g control, and rotating vertically to examine clinostat effects other than gravity compensation. Triticum at 1 g follows the well-established pattern of other cereal coleoptiles with a first positive curvature at low doses, followed by an indifferent response region, and a second positive response at progressively increasing doses. However, these response regions lie at higher dose levels than reported for Avena. There is no significant difference between the responses observed with the clinostat axis vertical in the rotating and stationary modes, but gravity compensation by horizontal rotation increases the magnitude of first and second positive curvatures some threefold at 100 min after stimulation. The indifferent response is replaced by a significant curvature towards the light source, but remains apparent as a reduced curvature response at these dose levels.
Document ID
20040089824
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Heathcote, D. G.
(University College Cardiff, United Kingdom)
Bircher, B. W.
Brown, A. H.
Date Acquired
August 21, 2013
Publication Date
January 1, 1987
Publication Information
Publication: Planta
Volume: 170
ISSN: 0032-0935
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAS2-10553
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Program Space Biology
NASA Discipline Plant Biology
NASA Discipline Number 40-30

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