Wall yield threshold and effective turgor in growing bean leaves
E Van Volkenburgh1, R E Cleland
1Department of Botany, University of Washington, 98195, Seattle, WA, USA.
Planta
|November 19, 2013
Summary
Cell enlargement relies on cell-wall extensibility and growth-effective turgor (P e). Studies show P e, not just turgor pressure (P), is key for plant growth regulation.
Area of Science:
- Plant Physiology
- Cell Biology
- Biophysics
Background:
- Cell enlargement is driven by turgor pressure (P) overcoming cell-wall resistance.
- Growth-effective turgor (P e) is the turgor pressure exceeding the cell wall's yield threshold (Y).
- Understanding the interplay between P, Y, and P e is crucial for plant growth regulation.
Purpose of the Study:
- To investigate the relationship between cell turgor parameters and cell enlargement rate in Phaseolus vulgaris leaves.
- To determine whether changes in turgor pressure (P) or growth-effective turgor (P e) primarily regulate light-stimulated leaf growth.
- To assess the impact of environmental conditions on P, Y, and P e.
Main Methods:
- Measurements of turgor pressure (P) and yield threshold (Y) in growing bean leaves.
- Utilized an isopiestic psychrometer for P measurements.
- Employed the stress-relaxation method to determine Y and subsequently calculate P e.
Main Results:
- Light-stimulated rapid leaf growth led to decreases in P, Y, and P e.
- As leaves matured and growth slowed, Y decreased while P e increased.
- High humidity increased P but did not enhance growth rate; in some cases, Y tracked P, leaving P e unchanged.
Conclusions:
- Leaf growth rate is primarily controlled by cell-wall extensibility (m), not growth-effective turgor (P e).
- Measuring P e is more informative than P alone when correlating cell turgor with growth rates.
- Environmental factors influence P and Y, impacting P e and overall plant growth.
Related Concept Videos
00:53Tonicity in Plants
54.0K
Tonicity describes the capacity of a cell to lose or gain water. It depends on the quantity of solute that does not penetrate the membrane. Tonicity delimits the magnitude and direction of osmosis and results in three possible scenarios that alter the volume of a cell: hypertonicity, hypotonicity, and isotonicity. Due to differences in structure and physiology, tonicity of plant cells is different from that of animal cells in some scenarios.
54.0K
01:20Tonicity in Plants
25.5K
Plant cells maintain appropriate osmotic balance in extreme conditions. For instance, plants in dry environments store water in vacuoles, limit the opening of their stoma, and have thick, waxy cuticles to prevent unnecessary water loss. Some species of plants that live in salty environments store salt in their roots. As a result, water osmosis occurs in the root from the surrounding soil.
Tonicity
Tonicity describes the capacity of a cell to lose or gain water depending on the solute...
Tonicity
Tonicity describes the capacity of a cell to lose or gain water depending on the solute...
25.5K
02:41Responses to Drought and Flooding
10.2K
Water plays a significant role in the life cycle of plants. However, insufficient or excess of water can be detrimental and pose a serious threat to plants.
10.2K
02:16Light Acquisition
8.0K
In order to produce glucose, plants need to capture sufficient light energy. Many modern plants have evolved leaves specialized for light acquisition. Leaves can be only millimeters in width or tens of meters wide, depending on the environment. Due to competition for sunlight, evolution has driven the evolution of increasingly larger leaves and taller plants, to avoid shading by their neighbors with contaminant elaboration of root architecture and mechanisms to transport water and nutrients.
8.0K
01:57Adaptations that Reduce Water Loss
24.4K
Though evaporation from plant leaves drives transpiration, it also results in loss of water. Because water is critical for photosynthetic reactions and other cellular processes, evolutionary pressures on plants in different environments have driven the acquisition of adaptations that reduce water loss.
24.4K
02:04Regulation of Transpiration by Stomata
26.3K
During photosynthesis, plants acquire the necessary carbon dioxide and release the produced oxygen back into the atmosphere. Openings in the epidermis of plant leaves is the site of this exchange of gasses. A single opening is called a stoma—derived from the Greek word for “mouth.” Stomata open and close in response to a variety of environmental cues.
26.3K