a) concentration gradient. d. water is actively transported into the "source" region of the phloem to create the turgor pressure needed. So, according to Munch’s hypothesis the flow through the sieve tubes is passive, although there is evidence of involvement of metabolism in bulk flow. Secondly, concentration gradients of organic solutes are proved to be present between the sink and the source. A plant cell with a Ψs of -0.65 MPa maintains a constant volume when bathed in a solution that has a Ψs of … Companion cells control the rate and direction of movement of phloem sap. At the regions of lower pressure, sink cells remove the sucrose by active transport. Before moving into the source cells present in the phloem, the prepared food is converted into sucrose. c. the pressure in the phloem of a root is normally greater than the pressure in the phloem of a leaf. 2/27/2018 MasteringBiology: Ch 35 HW 1/1 ' Ù Part A According to the pressure­flow hypothesis, which direction are sucrose and water flowing in the phloem when roots are sources and leaves are sinks? 10. According to mass or passive flow hypothesis, two features are important for phloem transport of substances. kvargli6h and 50 others learned from this answer "The movement of water into a nutrient-rich region of the phloem decreases the pressure in that region" is the statement that is not true according to the pressure-flow hypothesis. There are different evidences that support the hypothesis. Osmotic pressure rises and phloem SAP moves from an area of higher osmotic pressure to the area of low pressure. These organs are interconnected at the whole-plant level by long-distance transport. According to the pressure-flow hypothesis of phloem transport, _____. a. solute moves from a high concentration in the source to a lower concentration in the sink b. the pressure of the phloem of a root is normally greater than the pressure in the phloem of a leaf c. the formation of starch from sugar in the sink increases the osmotic concentration 29) According to the pressure-flow hypothesis of phloem transport, A) solute moves from a high concentration in the "source" to a lower concentration in the "sink." According to the pressure-flow hypothesis of phloem transport, _____. Name the form of carbohydrates which is transported in plants as food. Besides water, sugars are one of the most important components involved in this transport. Glucose is produced by photosynthesis in the mesophyll cells of the green leaves, some of which is converted into nonreducing sugar, i.e., sucrose. According to the pressure-flow hypothesis, the sugar concentration gradient promotes the flow of water into the phloem, resulting in the generation of pressure. The hypothesis describes import rate (Rf) of a nutrient as: (1) R f = L p (P source − P sink) A C What are the components of phloem sap? Firstly, there is an exudation of solution from the phloem when the stem is cut or punctured by the mouthparts of an aphid, a classical experiment demonstrating the translocation function of phloem, indicating that the phloem sap is under pressure. An active removal of … Phloem sap is thought to play a role in sending informational signals throughout vascular plants. Munch postulated that solute movement occurred in the phloem along a turgor pressure gradient from source to sink. (leaves) II. Before moving into the source cells present in the phloem, the prepared food is converted into sucrose. 2. These are: I. Water moves from the xylem vessels into the adjacent phloem, thereby increasing the hydrostatic pressure in the phloem. As the sink cells pull the solute out of the phloem, water leaves the phloem by osmosis, passing to neighboring tissues that have higher solute concentrations. Mass flow hypothesis? According to the pressure flow hypothesis of phloem transport, V 03:59 Biology According to the pressure flow hypothesis of phloem transport, A) solute moves from a high concentration in the source to a lower concentration in the sink. At the sink again active transport is required to move the sugar out of the phloem SAP into the cell where the sugar is used to release energy by the process of respiration. The relevant points of pressure-flow mechanism are as follows: 1. d) osmosis and diffusion . Answers: 1. b) phloem translocation. According to pressure flow mechanism water containing sugar in solution flows under pressure through the phloem. 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