Question

Choose the correct combination regarding mechanism of translocation:

• A. Stem tip $\longrightarrow$ Sugar enters sieve tube $\longrightarrow$ water flows by diffusion.
• B. Leaf $\longrightarrow$ Sugar enters sieve tubes $\longrightarrow$ water flows by Osmosis.
• C. Stem $\longrightarrow$ Sugar solution flows to region of high turgor pressure $\longrightarrow$ water flows by Osmosis.
• D. Root $\longrightarrow$ Sugar enters sieve tube for metabolism and storage $\longrightarrow$ water flows by Osmosis.

Hint:

Always relate sugar loading and water movement in phloem to the source-sink concept for translocation questions.

Answer 1

The Correct Option is B

Explanation: In the translocation mechanism, sugar is loaded into the phloem at the source (usually the leaf), causing water to enter by osmosis due to increased solute concentration. This generates pressure that drives the flow toward sink tissues. Hence, the correct flow is from the leaf, where sugar enters sieve tubes, followed by water movement through osmosis.