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The mechanosensory calcium-selective ion channel: key component of a plasmalemmal control centre?Mechanosensory calcium-selective ion channels probably serve to detect not only mechanical stress but also electrical, thermal, and diverse chemical stimuli. Because all stimuli result in a common output, most notably a shift in second messenger calcium concentration, the channels are presumed to serve as signal integrators. Further, insofar as second messenger calcium in turn gives rise to mechanical, electrical, and diverse chemical changes, the channels are postulated to initiate regulatory feedbacks. It is proposed that the channels and the feedback loops play a wide range of roles in regulating normal plant function, as well as in mediating disturbance of normal function by environmental stressors and various pathogens. In developing evidence for the physiological performance of the channel, a model for a cluster of regulatory plasmalemmal proteins and cytoskeletal elements grouped around a set of wall-to-membrane and transmembrane linkers has proved useful. An illustration of how the model might operate is presented. It is founded on the demonstration that several xenobiotics interfere both with normal channel behaviour and with gravitropic reception. Accordingly, the first part of the illustration deals with how the channels and the control system within which they putatively operate might initiate gravitropism. Assuming that gravitropism is an asymmetric expression of growth, the activities of the channels and the plasmalemmal control system are extrapolated to account for regulation of both rate and allometry of cell expansion. Finally, it is discussed how light, hormones, redox agents and herbicides could in principle affect growth via the putative plasmalemmal control cluster or centre.
Document ID
20040090251
Document Type
Reprint (Version printed in journal)
Authors
Pickard, B. G. (Washington University St Louis, Missouri 63130-4899)
Ding, J. P.
Date Acquired
August 21, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Australian journal of plant physiology
Volume: 20
ISSN: 0310-7841
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAGW-1782
CONTRACT_GRANT: NAGW-3046
Distribution Limits
Public
Copyright
Other
Keywords
NASA Program Space Biology
Non-NASA Center
NASA Discipline Number 40-50
NASA Discipline Plant Biology