Question

Explain the pressure-flow hypothesis of translocation of sugars in plants.

Answer 1

In Plants, the mechanism explained for the translocation of sugars from source to sink is referred to as the pressure-flow hypothesis.

Glucose generated by photosynthesis at the source is converted to sucrose which is moved to the phloem sieve tube cells through the companion cell by active transport. The remaining transport in the phloem is carried out by the differences in the osmotic pressure, which facilitates the transport from higher pressure to lower pressure regions of the sink. Again by active transport, the sucrose is transported from phloem to the cells of the sink where it will be stored for a long.

Figure : Mass flow hypothesis