What does the pressure flow model state?
What does the pressure flow model state?
The Pressure-Flow Hypothesis It proposes that water containing food molecules flows under pressure through the phloem. The pressure is created by the difference in water concentration of the solution in the phloem and the relatively pure water in the nearby xylem ducts.
What is the pressure flow hypothesis for phloem transport?
The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges.
What happens during phloem transport?
Phloem consists of living cells arranged end to end. Phloem transports sucrose and amino acids up and down the plant. This is called translocation . In general, this happens between where these substances are made (the sources) and where they are used or stored (the sinks).
Which statement about the pressure flow model of fluid flow in phloem is true?
translocation. Which of the following statements about the pressure flow model of fluid flow in phloem is true? Fluid always flows in a downward direction from high pressure to low pressure. Pressure is exerted on fluid in phloem by changes in water volume due to evaporation from stomata.
Who proposed pressure flow model?
Ernst Münch
Introduction. In angiosperms, increasing evidence shows the pressure-flow hypothesis, formulated by Ernst Münch in 1930 [1••], to adequately explain the mechanism of phloem transport [2].
Which statement about the pressure flow model of fluid flow in the phloem is true?
What is transported in the phloem and what is the direction of transport starch up and down starch up only sucrose down and up sucrose down only?
Answer: The food in the form of sucrose is transported by the vascular tissue phloem. The transportation occurs in the direction of the source to sink. Transport of organic solutes from one part of the plant to the other through phloem sieve tubes is called translocation of organic solvents.
What is osmotic pressure in phloem?
Osmotic pressure is the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis. Translocation through the phloem is dependent on metabolic activity of the phloem cells. The water containing food molecules flows under pressure through the phloem.
Who proposed pressure flow theory?
