What mechanism helps plant cells maintain their structure in a hypotonic solution?

In a hypotonic solution, the concentration of solutes outside the plant cell is lower than that inside the cell, which causes water to flow into the cell by osmosis. This influx of water increases the internal pressure, or turgor pressure, within the cell. The cell wall plays a crucial role in this scenario.

The rigidity of the cell wall allows the plant to withstand this increased pressure without bursting. Essentially, the cell wall is composed of cellulose and provides a protective barrier that maintains the structural integrity of the cell. As the turgor pressure increases, the cell wall resists the expansion, thus keeping the cell intact and maintaining the plant’s overall structure. This mechanism is vital for plant cells to thrive in environments where they may absorb excess water, as it prevents them from undergoing lysis while also providing support to the plant structure as a whole.

The other options describe mechanisms that, while important in various contexts, do not directly address how plant cells maintain their structure specifically in a hypotonic solution. For instance, the expulsion of excess water is more characteristic of certain animal cells rather than plant cells, and the regulation of water channels or formation of protective layers around membranes do not have the same supportive role that the rigid cell wall provides