Related Experiment Video
Updated: Aug 8, 2026
11:30
Studying the Activity of Neuropeptides and Other Regulators of the Excretory System in the Adult Mosquito
Published on: August 24, 2021
Osmoregulation or turgor regulation in chara?
1Department of Biological Sciences, State University of New York at Buffalo, New York 14260.
Plant Physiology
|February 1, 1984
Summary
The freshwater alga Chara corallina maintains stable internal osmotic pressure against external changes. However, its osmoregulation is less effective with NaCl and sensitive to external pH.
Area of Science:
- Plant Physiology
- Algology
- Environmental Science
Background:
- Chara corallina, a freshwater alga, is studied for its physiological responses.
- Understanding osmoregulation is crucial for aquatic plant survival in changing environments.
Purpose of the Study:
- To investigate the osmoregulatory capacity of Chara corallina under various osmotic conditions.
- To determine the effects of different solutes (CaCl2, raffinose, NaCl) and environmental factors (pH, light) on Chara's turgor pressure.
Main Methods:
- Exposure of Chara corallina to increased external osmotic pressures using different solutes.
- Monitoring of internal osmotic pressure and turgor pressure.
- Manipulation of external pH and light exposure duration.
Main Results:
- Chara corallina effectively regulates internal osmotic pressure against elevated external osmotic pressure, leading to decreased turgor.
- Osmoregulation is efficient with CaCl2 and raffinose but less so with NaCl.
- Decreased external pH (to 5) reduces turgor, while increased pH (to 9) has no significant effect.
- Light duration (0.5 to 24 hours) does not impact turgor pressure.
Conclusions:
- Chara corallina exhibits robust osmoregulation, but its efficiency varies with osmotic challenge type.
- External pH is a critical factor influencing turgor pressure in this alga.
- Light intensity is not a primary regulator of turgor in Chara corallina under these experimental conditions.
Related Concept Videos
02:32Osmoregulation in Fishes
When cells are placed in a hypotonic (low-salt) fluid, they can swell and burst. Meanwhile, cells in a hypertonic solution—with a higher salt concentration—can shrivel and die. How do fish cells avoid these gruesome fates in hypotonic freshwater or hypertonic seawater environments?
02:12What Are Osmoregulation and Excretion?
Organisms must keep bodily fluids at a constant temperature and pH while maintaining specific solute concentrations in order to support life functions. Osmoregulation is the process that balances solute and water levels.
00:59Tonicity in Animals
The tonicity of a solution determines if a cell gains or loses water in that solution. The tonicity depends on the permeability of the cell membrane for different solutes and the concentration of nonpenetrating solutes in the solution within and outside of the cell. If a semipermeable membrane hinders the passage of some solutes but allows water to follow its concentration gradient, water moves from the side with low osmolarity (i.e., less solute) to the side with higher osmolarity (i.e.,...
01:16Tonicity in Animals
Tonicity describes the amount of solute in a solution. The measure of the tonicity of a solution, or the total amount of solutes dissolved in a specific amount of solution, is called its osmolarity. Three terms—hypotonic, isotonic, and hypertonic—are used to relate the osmolarity of a cell to the osmolarity of the extracellular fluid that contains the cells. In a hypotonic solution, such as tap water, the extracellular fluid has a lower concentration of solutes than the fluid inside the cell,...
01:20Tonicity in Plants
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...
00:53Tonicity in Plants
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.Plants and Hypotonic EnvironmentsUnlike animal cells,...