Department of Botany, University of Washington, Seattle, WA 98195
This review article continues to be cited regularly two and a half decades after publication. It laid out the subcellular physics of gravity sensing that allowed rejection of many hypothetical sensing mechanisms and helped narrow the search. Excellent subsequent research met the challenge of the third excerpted paragraph below.
The physical behaviour of objects on a human scale is very different from that on the subcellular scale. It is easy, when imagining how gravity perception might work, to make erroneous assumptions about how various components will act. It is hoped to give the reader an intuitive grasp of how gravity acts on plant cells and how that may be turned into physiological information.
Some potential per- ception mechanisms will be evaluated in terms of their likelihood of per- forming as rapidly and as sensitively as does the true gravity-sensing system.
For progress in the study of gravity perception, it is essential to be able to study individual steps in gravitropism. Although it is unlikely that steps of gravity sensing can be isolated and studied in vitro, it must be possible to detect the function of individual steps. Of particular interest would be to correlate a signal intensity with details of statolith behaviour. It would then be possible to test hypotheses which predict that specific interactions between statoliths and other cellular components give rise to perception.