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Studies on the longitudinal and lateral transport of IAA in the shoots of etiolated corn seedlingsThe auxin, indole-3-acetic acid, and the symplastic probe, carboxyfluorescein diacetate, were applied to the cut mesocotyl base or coleoptile apex of etiolated Zea mays seedlings and their transport measured and tissue distribution determined. The longitudinal transport of indole-3-acetate was strongly basipolar, while that of carboxyfluorescein was essentially apolar. The longitudinal transport of IAA, like carboxyfluorescein, was mainly in the stele. IAA exhibited a much higher lateral mobility from stele to cortex than did carboxyfluorescein. Based on the calculation of moles probe/kg fw, IAA is 4 times more concentrated in the stele than in the cortex while CF is 24 times higher in concentration in the stele than in the cortex. The structure of the node and the mesocotyl regions just below the node, regions of maximum growth, were examined and plasmodesmatal structure and frequency in these regions determined. The plasmodesmatal frequency, about 3 per micrometer2, between all cell types of the mesocotyl was found to be about 5-8 fold higher than that found for the root. Hypotheses of lateral auxin transport are discussed.
Document ID
20040090165
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Epel, B. L.
(Tel Aviv Univ. Israel)
Warmbrodt, R. P.
Bandurski, R. S.
Date Acquired
August 21, 2013
Publication Date
August 1, 1992
Publication Information
Publication: Journal of plant physiology
Volume: 140
Issue: 3
ISSN: 0176-1617
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: DMB-850423
CONTRACT_GRANT: NAG2-362
CONTRACT_GRANT: NAGW-97
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 40-50
Non-NASA Center
NASA Program Space Biology
NASA Discipline Plant Biology

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