Resistance of plants to gravitational force
- 517 Downloads
Developing resistance to gravitational force is a critical response for terrestrial plants to survive under 1 × g conditions. We have termed this reaction “gravity resistance” and have analyzed its nature and mechanisms using hypergravity conditions produced by centrifugation and microgravity conditions in space. Our results indicate that plants develop a short and thick body and increase cell wall rigidity to resist gravitational force. The modification of body shape is brought about by the rapid reorientation of cortical microtubules that is caused by the action of microtubule-associated proteins in response to the magnitude of the gravitational force. The modification of cell wall rigidity is regulated by changes in cell wall metabolism that are caused by alterations in the levels of cell wall enzymes and in the pH of apoplastic fluid (cell wall fluid). Mechanoreceptors on the plasma membrane may be involved in the perception of the gravitational force. In this review, we discuss methods for altering gravitational conditions and describe the nature and mechanisms of gravity resistance in plants.
KeywordsCell wall rigidity Gravity resistance Growth anisotropy Hypergravity Mechanoreceptor Microgravity
The author is grateful to numerous colleagues and collaborators. Thanks are also due to Professor T. Hoson and Dr. K. Wakabayashi of Osaka City University for critical reading of the manuscript and valuable suggestions. The present study was supported in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Grant for Ground-based Research for Space Utilization from Japan Space Forum, and by Sasakawa Scientific Research Grant from the Japan Science Society.
- Erhardt M, Stoppin-Mellet V, Campagne S, Canaday J, Mutterer J, Fabian T, Sauter M, Muller T, Peter C, Lambert AM, Schmit AC (2002) The plant Spc98p homologue colocalizes with γ-tubulin at microtubule nucleation sites and is required for microtubule nucleation. J Cell Sci 115:2423–2431PubMedGoogle Scholar
- Jiang CJ, Sonobe S (1993) Identification and preliminary characterization of a 65 kDa higher-plant microtubule-associated protein. J Cell Sci 105:891–901Google Scholar
- Nakabayashi I, Karahara I, Tamaoki D, Masuda K, Wakasugi T, Yamada K, Soga K, Hoson T, Kamisaka S (2006) Hypergravity stimulus enhances primary xylem development and decreases mechanical properties of secondary cell walls in inflorescence stems of Arabidopsis thaliana. Ann Bot 97:1083–1090PubMedCrossRefGoogle Scholar
- Sievers A, Buchen B, Volkmann D, Hejnowicz Z (1991) Role of the cytoskeleton in gravity perception. In: Lloyd CW (ed) The cytoskeletal basis of plant growth and form. Academic Press, London, pp 169–182Google Scholar
- Wayne R, Staves MP (1997) A down-to earth model of gravisensing. Gravi Space Biol Bull 10:57–64Google Scholar