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Effect of calmodulin antagonists on the growth and graviresponsiveness of primary roots of maizeWe examined the effect of calmodulin (CaM) antagonists applied at the root tip on root growth, gravity-induced root curvature, and the movement of calcium across the root tip and auxin (IAA) across the elongation zone of gravistimulated roots. All of the CaM antagonists used in these studies delayed gravity-induced curvature at a concentration (1 micromole) that did not affect root growth. Calmodulin antagonists (> or = 1 micromole) inhibited downward transport of label from 45Ca2+ across the caps of gravistimulated roots relative to the downward transport of 45Ca2+ in gravistimulated roots which were not treated with CaM antagonists. Application of CaM antagonists at the root tip (> or = 1 micromole) also decreased the relative downward movement of label from 3H-IAA applied to the upper side of the elongation zone of gravistimulated roots. In general, tip application of antagonists inhibited neither the upward transport of 45Ca2+ in the root tip nor the upward movement of label from 3H-IAA in the elongation zone of gravistimulated roots. Thus, roots treated with CaM antagonists > or = 1 micromole become less graviresponsive and exhibit reduced or even a reversal of downward polarity of calcium transport across the root tip and IAA transport across the elongation zone. The results indicate that calmodulin-regulated events play a role in root gravitropism.
Document ID
20040090418
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Stinemetz, C. L.
(Rhodes College Memphis, TN 38112)
Hasenstein, K. H.
Young, L. M.
Evans, M. L.
Date Acquired
August 21, 2013
Publication Date
November 1, 1992
Publication Information
Publication: Plant growth regulation
Volume: 11
Issue: 4
ISSN: 0167-6903
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: PCM 8305775
CONTRACT_GRANT: DMB 8608673
CONTRACT_GRANT: NAGW-297
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
NASA Discipline Number 40-50
Non-NASA Center
NASA Program Space Biology

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