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Magnetophoretic induction of curvature in coleoptiles and hypocotylsColeoptiles of barley (Hordeum vulgare) were positioned in a high gradient magnetic field (HGMF, dynamic factor gradient of H(2)/2 of 10(9)-10(10) Oe2 cm-1), generated by a ferromagnetic wedge in a uniform magnetic field and rotated on a 1 rpm clinostat. After 4 h 90% of coleoptiles had curved toward the HGMF. The cells affected by HGMF showed clear intracellular displacement of amyloplasts. Coleoptiles in a magnetic field next to a non-ferromagnetic wedge showed no preferential curvature. The small size of the area of nonuniformity of the HGMF allowed mapping of the sensitivity of the coleoptiles by varying the initial position of the wedge relative to the coleoptile apex. When the ferromagnetic wedge was placed 1 mm below the coleoptile tip only 58% of the coleoptiles curved toward the wedge indicating that the cells most sensitive to intracellular displacement of amyloplasts and thus gravity sensing are confined to the top 1 mm portion of barley coleoptiles. Similar experiments with tomato hypocotyls (Lycopersicum esculentum) also resulted in curvature toward the HGMF. The data strongly support the amyloplast-based gravity-sensing system in higher plants and the usefulness of HGMF to substitute gravity in shoots.
Document ID
20040089309
Acquisition Source
Kennedy Space Center
Document Type
Reprint (Version printed in journal)
Authors
Kuznetsov, O. A.
(University of Southwestern Louisiana Lafayette 70504-2451, United States)
Hasenstein, K. H.
Date Acquired
August 21, 2013
Publication Date
November 1, 1997
Publication Information
Publication: Journal of experimental botany
Volume: 48
Issue: 316
ISSN: 0022-0957
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAG10-0190
CONTRACT_GRANT: NAGW-3565
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
Non-NASA Center

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