The symplastic and apoplastic transport systems are two different pathways by which photosynthates (products of photosynthesis) are transported through the phloem in plants.
1. Symplastic Transport System:
- In the symplastic pathway, photosynthates move via the cytoplasmic continuum, which includes plasmodesmata, tiny channels connecting neighboring cells.
- Once photosynthates are produced in the mesophyll cells of the leaf, they enter the symplast and pass through plasmodesmata to neighboring cells.
- This transport system involves movement through the living cells, particularly the cytoplasm.
- The symplastic pathway is generally considered to be slower but more controlled, as all molecules must pass through living cells before reaching the phloem.
2. Apoplastic Transport System:
- In the apoplastic pathway, photosynthates move through the non-living spaces outside the cells.
- The transport occurs through the cell walls and extracellular spaces of plant tissues.
- Photosynthates can move freely between adjacent cells without crossing cell membranes.
- The apoplastic pathway is generally considered to be faster but less regulated compared to the symplastic pathway.
In conclusion, the symplastic transport system involves movement through the living cells of plants via plasmodesmata, while the apoplastic transport system involves movement through non-living spaces and the cell walls. Both systems play important roles in transporting photosynthates from the site of production (such as leaves) to the rest of the plant.
PHOTOSYNTHATES ARE TRANSPORTEDTHROUGH PHLOEM BY SYMPLASTIC OR APOPLASTIC TRANSPORT SYSTEMS. GIVE A CHARACTERIZATION OF THE TWO TRANSPORT SYSTEM.
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