While the phloem primarily transports sugars and other nutrients, the extent to which it carries CO2 is not definitively known, and available data is lacking.
Although the main function of phloem is to transport sugars produced during photosynthesis from source (e.g., leaves) to sink tissues (e.g., roots, fruits), it is possible that CO2 is also transported within the phloem. Leaf respiration produces CO2, and some CO2 is also delivered via the xylem. This combined CO2 contributes to the overall CO2 efflux from the leaf. However, the specific contribution of the phloem to CO2 transport requires further research.
Here's a breakdown:
- Primary Role: Phloem's well-established function is the translocation of photoassimilates, mainly sucrose.
- CO2 Transport Possibility: The question of whether phloem carries CO2 is less clear, with very little published data to support it.
- Source of CO2: CO2 in leaves originates from leaf respiration and xylem transport.
- Further Research Needed: Determining the exact role of phloem in CO2 transport needs more investigation.
In summary, while phloem's primary role is sugar transport, the possibility of CO2 transport is uncertain due to the lack of available data.
