The Importance of Turgor Pressure in Plant Cells

What causes turgor pressure in plant cells?

A. Water is being used up in photosynthesis.

B. Cells contain water vacuoles that are full of water.

C. Cells are losing water from their water vacuoles.

D. Water is being evaporated from the leaves.

Answer:

Turgor pressure occurs in plant cells when their water vacuoles are full, providing rigidity to the plant's structure in a hypotonic solution. Loss of turgor pressure causes wilting, as seen in under-watered plants. Tonicity and osmotic pressure play crucial roles in maintaining plant turgidity.

Plants exhibit turgor pressure in response to the water content within their cells. Specifically, turgor pressure is most evident when cells contain water vacuoles that are full of water. This occurs as water enters the cell, creating osmotic pressure that causes the vacuoles to expand, thereby exerting pressure against the cell walls and keeping the plant tissues firm and upright. This process is essential for plant rigidity and it occurs in a hypotonic solution where the external environment has a lower concentration of solutes compared to the inside of the cell.

Turgor pressure is important for the overall structure and health of plants. For instance, if a plant cell is placed in a hypertonic solution, water will leave the cell leading to a loss of turgor pressure, which can cause the plant to wilt. Conversely, a continual supply of water maintains osmotic pressure required for the movement of water throughout the plant, supporting various physiological processes such as photosynthesis.

Examining figures like Figure 5.13 and Figure 5.14 can help understand the effects of turgor pressure on plants, showing healthy, turgid plants and wilted plants before and after the application of water. Osmoregulation mechanisms in plants ensure that they do not lyse in hypotonic conditions, unlike animal cells that lack a rigid cell wall.