Investigate and explain the effects on plant tissues of immersing them in solutions of different concentrations, using the terms turgid, turgor pressure, plasmolysis and flaccid

Sourav PanNovember 2, 2024

Answered

When plant tissues are immersed in solutions of varying concentrations, the effects of osmosis become evident, influencing their structure and physiological state. The terms turgid, turgor pressure, plasmolysis, and flaccid are essential in understanding these effects.

Effects of Different Concentration Solutions on Plant Tissues

1. Hypotonic Solutions

• Definition: A hypotonic solution has a lower concentration of solutes compared to the inside of the plant cells.
• Effect on Plant Cells: When plant cells are placed in a hypotonic solution, water moves into the cells through osmosis because the water potential outside is higher than inside.
• Result: This influx of water causes the cells to swell and become turgid. The increased internal pressure (known as turgor pressure) pushes against the rigid cell wall, providing structural support and keeping the plant upright. Turgid cells are crucial for maintaining the overall health and function of plants.

2. Isotonic Solutions

• Definition: An isotonic solution has an equal concentration of solutes compared to the inside of the plant cells.
• Effect on Plant Cells: In isotonic conditions, there is no net movement of water into or out of the cells; water moves in and out at equal rates.
• Result: The plant cells remain in a stable state, maintaining their shape without becoming turgid or flaccid. However, they do not benefit from the structural support provided by turgor pressure.

3. Hypertonic Solutions

• Definition: A hypertonic solution has a higher concentration of solutes compared to the inside of the plant cells.
• Effect on Plant Cells: When plant cells are placed in a hypertonic solution, water moves out of the cells through osmosis because the water potential inside is higher than outside.
• Result: This loss of water leads to a decrease in turgor pressure, causing the cells to become flaccid and eventually leading to plasmolysis, where the cell membrane pulls away from the cell wall. Plasmolysis can severely impair cell function and lead to wilting or death if prolonged.

Importance of Water Potential Gradient

The movement of water during osmosis is driven by differences in water potential:

• Water Potential Gradient: Water moves from areas of higher water potential (lower solute concentration) to areas of lower water potential (higher solute concentration). This gradient is crucial for determining whether a plant cell will take up or lose water.
• Uptake and Loss of Water: In practical terms, this means that roots absorb water from moist soil (hypotonic environment), while leaves may lose water to drier air (hypertonic environment), helping plants regulate hydration levels.