Question

The mechanism of transfer of sugar in phloem, from source to sink is called as

• A. Osmotic flow
• B. Pressure flow
• C. Imbibition
• D. None of the above

Answer 1

Answer: (B)

Pressure flow

The mechanism which is used to transfer the sugar in phloem from source end to the sink end is called as the pressure flow mechanism. The sugar molecules are transported by the conducting cells in the phloem tissue in the form of sucrose. These sugar molecules are transported from the source end to the sink end. The source end is the region where the sugar is present in high concentrations. The sugar needs to be moved in the sieve elements in the source end by the process of sieve elements. Energy needs to be spent to move the sugar molecules in the form of ATP. The sugar molecules are transported through osmosis and removed from the sieve cells in the sink end by active transport.

Thus, the correct answer is option B.