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Computer based imaging and analysis of root gravitropismTwo key issues in studies of the nature of the gravitropic response in roots have been the determination of the precise pattern of differential elongation responsible for downward bending and the identification of the cells that show the initial motor response. The main approach for examining patterns of differential growth during root gravitropic curvature has been to apply markers to the root surface and photograph the root at regular intervals during gravitropic curvature. Although these studies have provided valuable information on the characteristics of the gravitropic motor response in roots, their labor intensive nature limits sample size and discourages both high frequency of sampling and depth of analysis of surface expansion data. In this brief review we describe the development of computer-based video analysis systems for automated measurement of root growth and shape change and discuss some key features of the root gravitropic response that have been revealed using this methodology. We summarize the capabilities of several new pieces of software designed to measure growth and shape changes in graviresponding roots and describe recent progress in developing analysis systems for studying the small, but experimentally popular, primary roots of Arabidopsis. A key finding revealed by such studies is that the initial gravitropic response of roots of maize and Arabidopsis occurs in the distal elongation zone (DEZ) near the root apical meristem, not in the main elongation zone. Another finding is that the initiation of rapid elongation in the DEZ following gravistimulation appears to be related to rapid membrane potential changes in this region of the root. These observations have provided the incentive for ongoing studies examining possible links between potential growth modifying factors (auxin, calcium, protons) and gravistimulated changes in membrane potential and growth patterns in the DEZ.
Document ID
20040089481
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Evans, M. L.
(The Ohio State University Columbus 43210, United States)
Ishikawa, H.
Date Acquired
August 21, 2013
Publication Date
June 1, 1997
Publication Information
Publication: Gravitational and space biology bulletin : publication of the American Society for Gravitational and Space Biology
Volume: 10
Issue: 2
ISSN: 1089-988X
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: IBN9-421856
CONTRACT_GRANT: IBN9-416015
CONTRACT_GRANT: NAGW-4522
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Plant Biology
Non-NASA Center
Review, Tutorial
Review

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