Which statement describes translocation?
A) the movement of amino acids and sucrose from the source to the sink in phloem
B) the movement of amino acids and sucrose from the source to the sink in xylem
C) the movement of amino acids and sucrose from the sink to the source in phloem
D) the movement of amino acids and sucrose from the sink to the source in xylem
▶️ Answer/Explanation
Ans: A
Translocation is the process of transporting organic nutrients (like sucrose and amino acids) from the source (e.g., leaves) to the sink (e.g., roots, fruits) through the phloem (A).
Xylem (B, D) transports water and minerals, not organic compounds. Movement from sink to source (C, D) is incorrect, as translocation is unidirectional (source → sink). Thus, the correct answer is A.
Dodder is a plant that grows on other plants called hosts. The dodder plant connects to the host’s vascular bundles. The dodder plant does not have green leaves or roots. What correctly describes the regions for translocation?
▶️ Answer/Explanation
Ans: C
Dodder is a parasitic plant that lacks chlorophyll and depends entirely on its host for nutrients. Translocation in plants occurs in the phloem, which transports organic nutrients (like sucrose) from source (photosynthetic tissues) to sink (growing or storage tissues).
Since dodder has no leaves (source), it draws nutrients from the host’s phloem. The diagram shows that Region X (host) is the source, and Region Y (dodder) is the sink, matching Option C.