Difference Between Flaccid and Plasmolysed Cells - Testbook.com

In the realm of plant biology, the terms flaccid and plasmolysed are often used to describe the state of plant cells under certain conditions. These conditions typically involve the movement of water into or out of the cells, which in turn influences the turgor pressure - the pressure exerted by the cell's contents against the cell wall. This article will delve into the characteristics of both flaccid and plasmolysed cells, and highlight their key differences.

Understanding Flaccid Cells

Flaccid cells are characterized by a lack of turgidity, which means they appear loose or saggy. This is because the cell's contents have shrunk and pulled away from the cell wall.

Flaccidity in plant cells occurs when they are placed in isotonic solutions - solutions that have the same concentration of solutes as the cell's contents.

In this state, the cell's plasma membrane is not pressed against the cell wall, which is the condition that lies between plasmolysis and turgidity.

The water potential within the cells is greater than that of the surrounding solution, causing water molecules to exit the cell through a process known as exosmosis. This reduces the turgor pressure to some extent.

The movement of water continues until the water potential on both sides of the plasma membrane becomes equal. As such, flaccid cells do not experience any net movement of water across the plasma membrane.

Understanding Plasmolysed Cells

Plasmolysed cells are those that have lost a significant amount of their cytoplasmic water due to being in a hypertonic solution.

The concentration of solutes in the surrounding solution is higher than that within the cell's cytoplasm. As a result, the water potential of the cytoplasm is greater, causing water molecules to move from the cell to the surrounding solution until equilibrium is reached.

This movement of water across a semipermeable membrane is known as osmosis. In this case, as the water moves out of the cell, the process is referred to as exosmosis. The loss of water eventually results in a decrease in the turgor pressure within the cytoplasm.

Comparing Flaccid and Plasmolysed Cells

Here are the main differences between flaccid and plasmolysed cells.

Flaccid Cells

Plasmolysed Cells

Occurrence

Occur in isotonic solutions.

Occur in hypertonic solutions.

Endosmosis vs Exosmosis

Endosmosis and exosmosis occur at the same rate.

Exosmosis leads to water being removed from the protoplasm.

The Protoplasm

The protoplasm does not exert pressure on the cell walls.

The protoplasm contracts.

State of Plant Cells in Different Solutions

The cells become suspended in isotonic solutions.

The cells become suspended in hypertonic solutions.

Water Potential of the Protoplasm

Equal to the surrounding solution.

Less than the surrounding solution.

Turgor Pressure of the Protoplast

The cells have no turgor pressure.

The cells have no turgor pressure and appear shrunken.

We hope this article has helped clarify the differences between flaccid and plasmolysed cells. For more such informative content, stay tuned.

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Frequently Asked Questions

What are Flaccid cells?

Flaccid cells correspond to a cell lacking turgidity. They are not plump and swollen but floppy or loose, and cells have drawn in and pulled away from the cell wall.

What are Plasmolysed cells?

Plasmolysed cells are those which tend to lose cytoplasmic water when in hypertonic solutions.

When does a cell become Flaccid?

A cell becomes flaccid when put in isotonic solutions.

When does a cell become Plasmolysed?

A cell becomes plasmolysed when put in hypertonic solutions.