examples of source cells and sink cells in the phloem

Answer 1

Source cells in the phloem are those that produce and load sugars, while sink cells are those that utilize and unload sugars. Here are some examples:

Source cells:
1. Mature leaves: Mature leaves are the primary source of photosynthesis and produce sugars through this process.
2. Storage organs: Storage organs like tubers and roots store sugars during periods of high photosynthetic activity and act as sources when sugars are needed.
3. Growing tissues: Growing tissues such as shoot and flower tips are actively dividing and require a constant supply of sugars for growth and development.
4. Seeds: Seeds contain stored energy in the form of sugars, which serve as a source during germination when roots and shoots develop.

Sink cells:
1. Developing fruits: Developing fruits are strong sink tissues as they require sugars for growth, ripening, and production of seeds.
2. Root tips: Root tips actively absorb water and minerals, and rely on sugars for energy to execute this process.
3. Developing flowers: Developing flowers require sugars for their growth and to attract pollinators.
4. Storage organs: During periods of low photosynthetic activity, storage organs like tubers and bulbs act as sinks and store sugars.

It is important to note that cells can switch between being a source and a sink depending on their metabolic needs. Additionally, the movement of sugars in the phloem is bidirectional, allowing for the transport of sugars from source to sink and vice versa.