Question

Munch hypothesis is based on
a. Translocation of food due to Turgor Pressure (TP) gradient and imbibition force.
b. Translocation of food due to the Turgor Pressure (TP) gradient.
c. Translocation of food due to imbibition force.
d. None of the above.

Answer 1

Munch hypothesis is also called the pressure-flow hypothesis. It explains the movement of sap through the phloem.

Complete Answer:
The Munch hypothesis was proposed by Ernest Munch in 1930. According to this theory, the organic substances move the region of high osmotic to the region of low osmotic pressure in a mass flow due to the development of a gradient of turgor pressure.

Option a: Munch hypothesis is based on the movement of phloem sap along a turgor pressure gradient. Therefore, this is an incorrect option.
Option b: The Munch hypothesis explains the movement of sap through the phloem. The high concentration of organic substances inside the cells of the phloem at a source creates the diffusion gradient drawing water from the adjacent xylem resulting in the turgor pressure. Therefore, this is the correct option.
Option c: Translocation of food occurs only due to the turgor pressure gradient. Therefore, this is an incorrect option.
Option d: Translocation of food occurs only due to the turgor pressure gradient. Therefore, this is an incorrect option.

Hence the correct answer is option ‘b’.

Note: The Munch hypothesis experiment was done by using two osmometers with differences in concentrations. This theory proved that movement of food from the leaves to the lower part of the plants, i.e. roots.