Related Experiment Video
Updated: Aug 8, 2026
12:18
A Strategy to Validate the Role of Callose-mediated Plasmodesmal Gating in the Tropic Response
Published on: April 17, 2016
Emergent growth: an auxin-mediated response
1Section of Genetics, Development and Physiology, Division of Biological Sciences, Cornell University, Ithaca, New York 14853.
Plant Physiology
|April 1, 1977
Summary
Pea stem segments exhibit "emergent growth," elongating significantly more after anoxia when re-oxygenated. This enhanced elongation is linked to auxin release, not anaerobic respiration byproducts or acid growth.
Area of Science:
- Plant Physiology
- Molecular Biology
- Biochemistry
Background:
- Plant stems exhibit complex growth responses to environmental conditions.
- Anoxia (oxygen deprivation) can trigger unique physiological changes in plants.
- Auxin (indoleacetic acid) is a key plant hormone regulating cell elongation.
Purpose of the Study:
- To investigate the mechanism behind "emergent growth" in pea stem segments after anoxia.
- To determine if anaerobic respiration byproducts or acid growth contribute to this phenomenon.
- To explore the role of auxin in mediating emergent growth.
Main Methods:
- Exposure of pea stem segments to anoxia for varying durations (15 minutes to 2 hours).
- Restoration of oxygenated conditions and measurement of stem segment elongation.
- Use of fluoride (F-) to inhibit anaerobic respiration.
- Monitoring of extracellular pH changes.
- Tracing of (14)C-indoleacetic acid to assess auxin mobility.
Main Results:
- Stem segments showed 100-200% greater elongation after anoxia compared to continuous aeration.
- Emergent growth occurred even with fluoride, an inhibitor of anaerobic respiration.
- No significant drop in extracellular pH was observed, ruling out direct acid growth.
- Studies with (14)C-indoleacetic acid indicated auxin was released from a previously unavailable pool during anoxia.
Conclusions:
- Emergent growth is not directly caused by a buildup of glycolytic products or acid growth.
- The enhanced elongation is likely a response to auxin released during anoxia.
- Newly mobile auxin promotes growth upon return to oxygenated conditions.
Related Concept Videos
02:26Responses to Gravity and Touch
Gravitropism: Plant Responses to Gravity
02:36Meristems and Plant Growth
Plants grow throughout their lives; this is called indeterminate growth, and it distinguishes plants from most animals. Although certain parts of plants stop growing (e.g., leaves and flowers), others grow continuously—like roots and stems.
01:56Plant Hormones
Plant hormones—or phytohormones—are chemical molecules that modulate one or more physiological processes of a plant. In animals, hormones are often produced in specific glands and circulated via the circulatory system. However, plants lack hormone-producing glands.
01:56Plant Hormones
Plant hormones—or phytohormones—are chemical molecules that modulate one or more physiological processes of a plant. In animals, hormones are often produced in specific glands and circulated via the circulatory system. However, plants lack hormone-producing glands.
02:19Morphogenesis
Plant morphogenesis—the development of a plant’s form and structure—involves several overlapping developmental processes, including growth and cell differentiation. Precursor cells differentiate into specific cell types, which are organized into the tissues and organ systems that make up the functional plant.
01:25Cell Signaling in Plants
Plant cells communicate to coordinate their cycle of growth, flowering and fruiting, and activities in roots, shoots, and leaves in response to the changing environmental conditions. Plant signaling is distinct from animal signaling. Plants primarily utilize enzyme-linked receptors, whereas the largest class of cell-surface receptors in animals are G-protein coupled receptors (GPCRs). Unlike animals, receptor tyrosine kinases are rare in plants. Instead, plants have a diverse class of...