The pressure flow hypothesis is also known as the Munch flow hypothesis which is proposed by E. Munch in 1930. This theory explains how the translocation of the solutes occurs in plants. As a result of photosynthesis there is higher concentration of the organic food materials in the mesophyll. Since the solute concentration is higher the osmotic pressure is also become high in the mesophyll cells. When the water enters the mesophyll cells the turgor pressure increases. This increase in the turgor pressure which will results in the mass flow of organic solute through the phloem down from the stem to the root. In all the cells the photosynthate are consumed or converted into the insoluble form for the storage and the excess amount of the water is converted into the soluble form.
