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The microtubule cytoskeleton does not integrate auxin transport and gravitropism in maize rootsThe Cholodny-Went hypothesis of gravitropism suggests that the graviresponse is controlled by the distribution of auxin. However, the mechanism of auxin transport during the graviresponse of roots is still unresolved. To determine whether the microtubule (MT) cytoskeleton is participating in auxin transport, the cytoskeleton was examined and the movement of 3H-IAA measured in intact and excised taxol, oryzalin, and naphthylphthalamic acid (NPA)-treated roots of Zea mays cv. Merit. Taxol and oryzalin did not inhibit the graviresponse of roots but the auxin transport inhibitor NPA greatly inhibited both auxin transport and graviresponse. NPA had no effect on MT organization in vertical roots, but caused MT reorientation in horizontally placed roots. Regardless of treatment, the organization of MTs in intact roots differed from that in root segments. The MT inhibitors, taxol and oryzalin had opposite effects on the MTs, namely, depolymerization (oryzalin) and stabilization and thickening (taxol), but both treatments caused swelling of the roots. The data indicate that the MT cytoskeleton does not directly interfere with auxin transport or auxin-mediated growth responses in maize roots.
Document ID
20040089005
Acquisition Source
Kennedy Space Center
Document Type
Reprint (Version printed in journal)
Authors
Hasenstein, K. H.
(University of Southwestern Louisiana Lafayette 70504-2451, United States)
Blancaflor, E. B.
Lee, J. S.
Date Acquired
August 21, 2013
Publication Date
April 1, 1999
Publication Information
Publication: Physiologia plantarum
Volume: 105
Issue: 4
ISSN: 0031-9317
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAGW-3565
CONTRACT_GRANT: NAG10-0190
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
Non-NASA Center

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