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Role of Ca++ in Shoot GravitropismA cornerstone in the argument that Ca(2+) levels may regulate growth is the finding the EGTA promotes straight growth. The usual explanation for these results is that Ca(2+) chelation from cell walls results in wall loosening and thus accelerated straight growth. The ability of frozen-thawed Avena coleoptile tissue (subjected to 15g tension) to extend in response to EGTA and Quin II was examined. The EGTA when applied in weakly buffered (i.e., 0.1mM) neutral solutions initiates rapid extension. When the buffer strength is increased, similar concentrations of EGTA produce no growth response. This implies when EGTA liberated protons are released upon Ca(2+) chelation they can either initiate acid growth (low buffer conditions) or if consumed (high buffer conditions) have no effect. Thus Ca(2+) chelation in itself apparently does not result in straight growth.
Document ID
19850017754
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Rayle, D. L.
(San Diego State Univ. San Diego, CA, United States)
Date Acquired
August 12, 2013
Publication Date
April 1, 1985
Publication Information
Publication: NASA. Washington NASA Space Biol. Program:
Subject Category
Life Sciences (General)
Accession Number
85N26065
Funding Number(s)
CONTRACT_GRANT: NAGW-230
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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