Characterizing the Physics of Plant Root Gravitropism: A Systems Modeling Approach
Abstract
The ability of plants to detect and respond to gravity is an essential characteristic for their survival. On Earth, the plant must direct its emerging roots downward in order to acquire the best possible chance of obtaining moisture and nutrients. When a seed germinates in any position other than with its root directly downward, the root and stem undergo a gravitropic response. Statoliths (gravity-sensing organelles) within the root cap respond to the gravitational force and, through a process that is yet not fully understood, induce differential growth along the root's elongation zone so that the root curves toward the downward direction. Research to date suggests that the statoliths perceive the off-vertical gravity signal by altering the tension and/or position of the cell's cytoskeletal components. This alteration produces a cascade of ion activity and cellular changes that leads to the differential growth pattern. Cells on the top side of the root elongate rapidly while those below are inhibited from growth. The general goal of this study is to model the plant root gravitropic response using classical controls and system identification principles. Specific objectives of this research include: (1) the development of a mathematical model of the physical principles governing the plant root gravity sensor (the statolith), (2) the development of a mathematical model for the differential growth response within the plant root's elongation zone, (3) the development of an overall (gravity input-to-curvature output) model through empirical analysis, and (4) the development of a model for the transduction mechanism through block diagram reduction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1999
- Accession Number
- ADA367698
Entities
People
- Thomas L. Yoder
Organizations
- University of Colorado Boulder