Test: Phloem Transport (Mass Flow Hypothesis) (Old NCERT) - JAMB MCQ

The sugars, synthesised in leaves (as a result of photosynthesis) are translocated downwards, upwards and laterally to all the other organs including storage organs mainly through phloem. These sugars are translocated in the form of sucrose.

Munch hypothesis is also called the pressure flow hypothesis, it explains the movement of sap through the phloem. It proposed by Ernest Munch in 1930. High concentration of organic substance inside the cell of the cells of the phloem at a source that creates the diffusion gradient drawing water from the adjacent xylem resulting into the turgor pressure.
So, the correct answer is 'Translocation of food due to turgor pressure gradient'.

Munch Hypothesis was about the theory on the translocation of organic solutes. In protoplasm of a sieve tube is connected through plasmodesmata and forms a continuous system which is called symplast. The translocation of solutes occurs in a mass along with cell sap through the sieve tubes form a region of higher turgor pressure (turgor pressure gradient).

The phloem sap needed to maintain a certain water potential (provided by water) and also an osmotic potential (provided by sucrose) for the components to get transported from source to sink in the plants. The water maintains the turgor pressure and helps the movement of sucrose from a hyperosmotic (source) to hypoosmotic (sink) locations, by maintaining the water potential.