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The endodermis and shoot gravitropism
1Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan. m-tasaka@bs.aist-nara.ac.jp
Trends in Plant Science
|May 14, 1999
Summary
Plant shoots exhibit negative gravitropism, while roots show positive gravitropism. New research indicates the endodermis is key for shoot gravity perception, suggesting a novel shoot gravitropism model.
Area of Science:
- Plant biology
- Genetics
- Developmental biology
Background:
- Higher plants display distinct gravitropic responses: shoots negatively gravitropic and roots positively gravitropic.
- Gravitropic mechanisms in plant roots, hypocotyls, and inflorescence stems differ.
- Mutant isolation in Arabidopsis has begun to elucidate these distinct pathways.
Purpose of the Study:
- To investigate the molecular and cellular basis of shoot gravitropism.
- To identify the specific tissues responsible for gravity perception in plant shoots.
Main Methods:
- Cytological analysis of shoot gravitropism mutants.
- Molecular characterization of Arabidopsis mutants, specifically sgrl and sgr7.
- Genetic analysis, including allelic identification with known genes like scarecrow (scr) and short-root (shr).
Main Results:
- Two mutants, shoot gravitropism 1 (sgrl) and sgr7, were analyzed.
- sgrl is allelic to scarecrow (scr), and sgr7 is allelic to short-root (shr).
- Analysis indicates the endodermis is the primary site of gravity perception in shoots.
Conclusions:
- The endodermis plays a crucial role in shoot gravitropism.
- These findings propose a new model for how plant shoots perceive and respond to gravity.