Explain pressure flow hypothesis of translocation of sugars in plants.
Mass flow or Pressure Flow Flypothesis : It was put forward by Munch (1927,1930). According to this hypothesis organic substance move from region of high osmotic pressure to low osmotic pressure due to turgor pressure. A high osmotic concentration is present in source e.g. mesophyll cells (due to photosynthesis). Sugar present in them passed into sieve tube therefore high osmotic concentration develops and it absorbs water from xylem and develop a high turgor pressure. It causes flow of sugar towards area of low turgor pressure or sink.
