Table of Contents
Definition:
The theory of the Mass flow hypothesis also known as the pressure-flow hypothesis describes the movement of fluid through the phloem, proposed by German physiotherapist Ernst Munch in 1930. forms a diffusion gradient that draws water from cells from the adjacent xylem. This improves turgor pressure in the phloem also called hydrostatic pressure.
Phloem movement occurs with a large flow from the sugar springs to the sugar sinks. The movement of the phloem is directed twice but not the same as each direction of the xylem cells. Because of this multi-sided flow, it is not uncommon for the milk in the filter tube to move in the opposite direction based on the fact that the milk cannot move easily between adjacent filter tubes.
Mechanism
When the movement of minerals and water by the xylem is mainly driven by negative pressure and the movement by the phloem is driven by hydrostatic pressure. This process is called translocation and is accompanied by a process known as phloem loading and unloading. Cells in sugar sources load the filter tube by causing the osmosis to increase the pressure pumping milk. Cells deliver solutes from sieve-tube components and produce opposite effects. The gradient of sugar from the source creates a pressure flow through the filter tube to the sink.
Glucose is produced by photosynthesis in mesophyll cells and some glucose is applied to cells during respiration. The remaining glucose is converted into undigested sugar.
Sucrose is transported to neighboring cells of small leaf veins.
Sucrose spreads from neighboring cells to the cells of the filter tube via plasmodesmata. Therefore, the amount of sucrose increases in the sieve tube structures.
Water travels from the adjacent xylem to the leaf vein through osmosis and raises the hydrostatic pressure of the filter tube elements.
Hydrostatic pressure transfers sucrose and other substances through a filter tube cell to the sink.
In the final sinks, sucrose is removed from the apoplast before entering the sink symplast.
Water flows out of the cells through osmosis and lowers hydrostatic pressure in them. Therefore, a pressure gradient is formed due to the infiltration of sugar into the well and the dissolution of sucrose in the sink.
Phloem sugar is eliminated by the root and stem cortex and is used for cellular respiration. Starch is insoluble and has no osmotic effect. Finally, pure water is left and is pumped to the xylem vessels by the respiratory tract.
Flow Hypothesis for Translocation
Munch’s Mass Flow Hypothesis is a theory that describes the movement of food items from concentration areas to areas of mind concentration slightly with phloem. Energy is needed to transfer live food from the phloem to the ground. This is due to variations in osmotic ability. Between feeding and receiving tissue, there is a turgor pressure gradient. The test was performed using two osmometers with different concentrations. This theory shows that food goes from the leaves to the roots. The leaves are regions that grow food and thus act as the only source. Roots are those regions that allow food to absorb and breathe. And the roots act as an end to the drainage. Flow from the end of the well to the end of the sink.
Pressure flow hypothesis of translocation of sugar in plants:
In plants, the described method of transporting sugar from the source to the deep is called the pressure-flow hypothesis.
The glucose produced by photosynthesis in the source is converted into sucrose which is transported to the cells of the phloem filter tube by a friendly cell by active transport. The remainder of the phloem is differentiated by osmotic pressure, which facilitates the transition from high pressure to low-pressure areas of the sink. And with active transport, sucrose is transported from the phloem to the sink cells where it will be stored for a long time.
Conclusion
Mass flow theory was proposed by German botanist Ernst Munch in 1930. It is said by the mass flow hypothesis that the transfer of glucose and other sugars into the phloem is caused by the constant flow of water and dissolved nutrients between the well (the place. Where sugar is produced) and the sink (where sugar is used). The diffusion gradient or osmotic gradient is caused by the high concentration of sugars and other organisms in the phloem source cells. This causes water to be drawn from the adjacent xylem and hydrostatic pressure to move the milk. The above theory is the closest available explanation for describing the flow of piles in the phloem.
Also read: ATP Adenosine Tri-Phosphate
FAQs
Describe the Mass Flow Hypothesis for the Transfer of Organic Solutes (Foods) to Plants.
Munch's Mass Flow Hypothesis is a theory that describes the movement of food items from concentration areas to areas of mind concentration slightly with phloem. Energy is needed to transfer live food from the phloem to the ground. This is due to variations in osmotic ability. Between feeding and receiving tissue, there is a turgor pressure gradient. The test was performed using two osmometers with different concentrations. This theory shows that food goes from the leaves to the roots. The leaves are regions that grow food and thus act as the only source. Roots are those regions that allow food to absorb and breathe. And the roots act as an end to the drainage. Flow from the end of the well to the end of the sink.
Why was Mass Flow Hypothesis so widely criticized?
The Mass Flow Hypothesis has met with criticism from most people. This is because many people believed that the transfer of particles to plants was not due to hydrostatic pressure, but rather to metabolic processes. Critics also disputed the Mass Flow Hypothesis statement, saying that the rate of transplantation is similar to this.
How does the transport process take place in plants?
There are two plant tissues responsible for the transport of plant material xylem and phloem. Xylem is responsible for the transport of water and minerals and phloem is responsible for the transport of food. The roots absorb water and minerals from the soil through the xylem to the leaves where they are used in the photosynthesis process. Food is processed with the help of photosynthesis and transported to various parts of the plant by Phloem.
