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

Any plant part that does not photosynthesize enough (or at all) to meet its own carbohydrate needs is a "sink" and must import sucrose via the phloem from photosynthetic "source" tissues (mainly mature green leaves).

In the source-to-sink model of translocation, photosynthetically active green leaves act as SOURCES, exporting the sugar (mainly sucrose) they manufacture through the phloem to tissues that cannot produce enough sugar themselves — the SINKS. Non-photosynthetic parts that therefore need a continuous supply of sucrose include:

1. Roots — being underground and non-green, they cannot photosynthesize, so all their sugar needs (for respiration, growth, and storage) are met by sucrose imported from the shoot.

2. Developing fruits and seeds — these growing reproductive structures require large amounts of sugar for growth and for laying down storage reserves (starch, oils, proteins), but they are usually not significantly photosynthetic themselves, especially as they mature, so they rely heavily on imported sucrose.

3. Storage organs — such as tubers (e.g., potato tubers), bulbs, corms, and rhizomes, which are typically underground/non-green and store large amounts of starch converted from imported sucrose.

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