explain the mass flow hypothesis on the translocation of solutes in plants?
Answers
Explanation:
Munch's Mass Flow Hypothesis is the theory which explains the flow of food materials through the phloem from the concentration regions to lower concentration regions. The force is needed to move organic food materials downwards in the phloem. This is caused due to differences in osmotic potential. There is a turgor pressure gradient exists between the supplying and receiving tissues. The experiment was performed using two osmometers with difference in concentrations. This theory proves that there is movement of food from the leaves to roots. The leaves are the regions where the food is produced and thus, serves as the source end. The roots are the regions which require food to perform absorption and respiration. Thus, the roots serves as sink end. The flow is from the source end to sink end....
Answer:
The pressure flow hypothesis, also known as the mass flow hypothesis, is the best-supported theory to explain the movement of sap through the phloem.[1][2] It was proposed by Ernst Münch, a German plant physiologist in 1930.[3] A high concentration of organic substances, particularly sugar, inside cells of the phloem at a source, such as a leaf, creates a diffusion gradient (osmotic gradient) that draws water into the cells from the adjacent xylem. This creates turgor pressure, also known as hydrostatic pressure, in the phloem. Movement of phloem sap occurs by bulk flow (mass flow) from sugar sources to sugar sinks. The movement in phloem is bidirectional, whereas, in xylem cells, it is unidirectional (upward). Because of this multi-directional flow, coupled with the fact that sap cannot move with ease between adjacent sieve-tubes, it is not unusual for sap in adjacent sieve-tubes to be flowing in opposite directions.
