Question

______ is a nonphotosynthetic plant organ or an organ that produces insufficient photosynthate to supply its own growth or needs of its storage.

• A. Source
• B. Sink
• C. Branch
• D. Storage organ

Hint:

In forest trees, developing seeds and fruits are powerful metabolic sinks that draw heavily on photosynthates, often temporarily reducing vegetative growth.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Plant growth and development depend on the allocation of carbohydrates from carbohydrate-producing organs to carbohydrate-consuming or carbohydrate-storing organs.
This allocation is regulated by source-sink relationships.

Step 2: Detailed Explation:
In plant physiology, the terms "Source" and "Sink" are defined based on net carbon balance:
- Source: A mature, photosynthetic organ (such as fully expanded leaves) that produces photosynthates in excess of its own requirements and exports them.
- Sink: A non-photosynthetic or growing plant organ (such as roots, tubers, developing buds, flowers, fruits, and young expanding leaves) that does not produce enough carbohydrates to meet its own metabolic and storage needs.
Sinks must import photosynthates from source organs to survive and grow.
Therefore, any organ that produces insufficient photosynthates to supply its own growth is classified as a sink.

Step 3: Fil Answer:
An organ that produces insufficient photosynthate to supply its own growth is called a sink.
Hence, the correct option is (B).