Chapter 7, Problem 42A

Summary Introduction

To analyze:

Farming and watering that is done in very dry regions of the world leave salts that accumulate in the soil as water evaporates. The reason that an increase in soil salinity have adverse effects on plant cells.

Introduction:

Osmosis: the diffusion of water through the selectively permeable membrane is called Osmosis. This process helps in maintaining homeostasis within the cell.

In any solution, a solute is the dissolved substance that is dissolved in the solvent.

Concentration is a measure of the amount of solute dissolved in a solvent.

Explanation of Solution

In the given situation, plant cells that are in direct contact with the soil are in hypertonic solution because the concentration of salt in the soil is increased.

In this condition, because of osmosis, the net movement of water is outside of the cell. As a result, plant cells start to lose water mainly from the central vacuole and the plasma membrane will shrink away from the cell wall. Excess loss of water hampers the homeostasis of the cell which adversely affects the functioning of the plant cells. This loss of water cause wilting in the plant cells.

Conclusion

Excess loss of water from the plant cell cause plasmolysis and if the hypertonic condition of the environment of the cell does not change, plant cell might die.