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Polyamines as Possible Modulators of Gravity-induced Calcium Transport in PlantsData from various laboratories indicate a probable relationship between calcium movement and some aspects of graviperception and tropistic bending responses. The movement of calcium in response to gravistimulation appears to be rapid, polar and opposite in direction to polar auxin transport. What might be the cause of such rapid Ca(2+) movement? Data from studies on polyamine (PA) metabolism may furnish a clue. A transient increase in the activity of ornithine decarboxylase (ODC) and titers of various PAs occurs within 60 seconds after hormonal stimulation of animal cells, followed by Ca(2+) transport out of the cells. Through the use of specific inhibitors, it was shown that the enhanced PA synthesis from ODC was essential not only for Ca(2+) transport, but also for Ca(2+) transport-dependent endocytosis and the movement of hexoses and amino acids across the plasmalemma. In plants, rapid changes in arginine decarboxylase (ADC) activity occur in response to various plant stresses. Physical stresses associated with gravisensor displacement and reorientation of a plant in the gravitational field could similarly activate ADC and that resultant increases in PA levels might initiate transient perturbations in Ca(2+) homeostasis.
Document ID
19850017749
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Galston, A. W.
(Yale Univ. New Haven, CT, United States)
Slocum, R. D.
(Yale Univ. New Haven, CT, 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
85N26060
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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