Q.List out the non-photosynthetic parts of a plant that need a supply of sucrose?

Step 1. Any plant organ that cannot manufacture its own food by photosynthesis is, by definition, a sink, and every sink depends on organic food imported through the phloem from photosynthesising source leaves.

Step 2. Roots are entirely non-photosynthetic (they receive no light underground) and rely completely on sucrose translocated down from the leaves for their respiration and growth.

Step 3. Storage organs such as tubers are also non-photosynthetic and accumulate imported sucrose, converting much of it into an insoluble storage form.

Step 4. Developing and immature fruits cannot photosynthesise enough to meet their own growth and ripening needs and so import sucrose as they enlarge.

Step 5. Young, immature leaves - before they turn fully green and become net exporters - are themselves net importers of sucrose from older, mature leaves until they mature into sources in their own right. …

Apply the source-sink definition (a sink is any organ that only receives, never exports, food) to list the or …

• Including mature, fully green leaves in the list, when mature leaves are normally sources, not sinks. …