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Gravisensing: ionic responses, cytoskeleton and amyloplast behavior
N Strömgren Allen1, P Chattaraj, D Collings
1Department of Botany, North Carolina State University, Raleigh, NC 27695-7612, USA. nina_allen@ncsu.edu
Advances in Space Research : the Official Journal of the Committee on Space Research (COSPAR)
|March 16, 2004
Summary
Plants perceive gravity using specialized cells containing amyloplasts. This study investigates how these amyloplasts interact with cellular structures and how calcium ion (Ca2+) fluxes are involved in the gravity response in moss filaments.
Area of Science:
- Plant biology
- Cell biology
- Biophysics
Background:
- Plants sense gravity via pulvinal tissue and amyloplasts in Zea mays.
- The mechanism of gravity signal transduction remains largely unknown.
- Cytoskeletal elements are hypothesized to link amyloplasts to cellular responses.
Purpose of the Study:
- To investigate amyloplast movement and its role in gravity perception.
- To explore the effects of actin and microtubule inhibitors on plastid sedimentation.
- To analyze calcium ion (Ca2+) influx patterns during gravistimulation in Physcomitrella patens.
Main Methods:
- Monitoring amyloplast movements in response to gravistimulation.
- Pharmacological disruption of actin and microtubule dynamics.
- Measuring Ca2+ influx using Ca2+ selective ion probes in moss filaments.
Main Results:
- Amyloplasts sediment in response to gravity changes, potentially interacting with cellular membranes via the cytoskeleton.
- Microtubule (MT) accumulation was observed on the lower flank of gravistimulated moss filaments.
- Ca2+ influx in moss filaments shifted from the apex to the upper side upon gravistimulation, indicating asymmetric channel activation.
Conclusions:
- Amyloplasts play a role in gravity perception, with potential involvement of the cytoskeleton in signal transduction.
- Gravistimulation induces asymmetric Ca2+ distribution in moss filaments, suggesting differential plasma membrane channel activity.