Effect of Turgor Pressure in Munch Hypothesis

Turgor pressure is the force within a plant cell that pushes the plasma membrane against the cell wall. The Munch hypothesis explains the mechanism of translocation of organic solutes in plants. According to this hypothesis, the movement of solutes in the phloem occurs due to the pressure gradient generated by the difference in solute concentration between source and sink cells. The pressure gradient is created by an increase in turgor pressure in the source cells and a decrease in turgor pressure in the sink cells.

Increase of Turgor Pressure

In the Munch hypothesis, the phloem translocation is driven by the pressure gradient between source and sink cells. The source cells are the leaves, where photosynthesis occurs, and the sink cells are the growing regions of the plant, such as roots, stems, and fruits. The source cells produce organic solutes, such as sucrose, and load them into the phloem. This process increases the solute concentration and turgor pressure in the source cells. The increased turgor pressure pushes the solutes from the source cells into the phloem sieve tubes.

The sink cells, on the other hand, have a lower solute concentration and turgor pressure compared to the source cells. This decrease in turgor pressure creates a pressure gradient that drives the movement of solutes from the source to the sink cells. The solutes are unloaded from the phloem sieve tubes into the sink cells, where they are used for growth and metabolic activities.

Therefore, the effect of turgor pressure in the Munch hypothesis is an increase in turgor pressure in the source cells, which drives the movement of solutes into the phloem sieve tubes, and a decrease in turgor pressure in the sink cells, which creates a pressure gradient that drives the movement of solutes from the phloem sieve tubes into the sink cells.