Explain pressure flow hypothesis of
translocation of sugars in plants.
Explain pressure flow hypothesis of translocation of sugars in plants.
According
to the pressure flow hypothesis, food is prepared in the plant leaves
in the form of glucose. Before moving into the source cells present
in the phloem, the prepared food is converted into sucrose. Water
moves from the xylem vessels into the adjacent phloem, thereby
increasing the hydrostatic pressure in the phloem. Consequently, the
sucrose moves through the sieve cells of the phloem. The sucrose
already present in the sink region is converted into starch or
cellulose, thereby reducing the hydrostatic pressure in the sink
cells. Hence, the pressure difference created between the source and
the sink cells allows sugars to be translocated from the former to
the latter. This starch or cellulose is finally removed from the sink
cells through active transport.
According to the pressure flow hypothesis, food is prepared in the plant leaves in the form of glucose. Before moving into the source cells present in the phloem, the prepared food is converted into sucrose. Water moves from the xylem vessels into the adjacent phloem, thereby increasing the hydrostatic pressure in the phloem. Consequently, the sucrose moves through the sieve cells of the phloem. The sucrose already present in the sink region is converted into starch or cellulose, thereby reducing the hydrostatic pressure in the sink cells. Hence, the pressure difference created between the source and the sink cells allows sugars to be translocated from the former to the latter. This starch or cellulose is finally removed from the sink cells through active transport.
