Search results
As a result, water moves from the phloem by osmosis and is then transpired or recycled via the xylem back into the phloem sap. Figure 4.5.2.4 4.5.2. 4: The pressure-flow hypothesis of assimilate transport. The assimilate, which is rich in sucrose, is actively transported from source cells into companion cells and then into the sieve-tube ...
- 4.5.3: Chapter Summary
Water and minerals move through the xylem, and sugars move...
- 4.5.3: Chapter Summary
9.2 U 3 Active transport is used to load organic compounds into phloem sieve tubes at the source. State that sucrose is the most prevalent solute in phloem sap. Outline why sucrose is used for phloem transport, as opposed to glucose. Describe the active transport of sucrose into the phloem via a co-transport protein.
This reduced water potential causes water to flow into the companion cells and sieve tube members via osmosis. This builds up turgor pressure inside the cells and allows the sieve tubes to transport sucrose via mass flow through the phloem from areas of high pressure in the source to areas of low pressure in the sinks.
Jul 11, 2023 · Xylem and phloem form the vascular system of a plant. Xylem transports water and minerals, while phloem transports food. The vascular system of plants consists of the xylem and phloem. They are somewhat like blood vessels in animals, but plants transport materials using two tissues rather than one. Here is a look at what xylem and phloem are ...
The entry of this water increases turgor pressure (causes a more positive pressure potential) at the source end of the sieve tube, so that the entire fluid content of the sieve tube is pushed toward the sink end of the tub e— in other words, the sap moves in response to a pressure gradient. In the sink, the sucrose is unloaded both passively and by active transport, and water moves back into ...
At the sink, solutes are actively removed from the sieve tube elements. This increases the water potential in sieve tube elements at the sink. Water leaves the phloem by osmosis, decreasing the hydrostatic pressure at the sink. This creates a pressure gradient, pushing solutes from the source to areas of lower pressure at the sink. At the sink ...
People also ask
How does water enter a sieve tube?
Why does phloem move from source to sink?
How does a phloem sieve work?
How does osmosis affect the concentration of water in a sieve tube?
How do organic molecules move from a source to a sink?
Do materials move from a source to a sink during translocation?
Aug 28, 2012 · This chapter briefly reviews the physiological processes considered to underpin flow to, through, and from, the phloem. It starts with an analysis of chemical species translocated. This information is then built into an overall appraisal of the principles governing flows from sources to sinks before dissecting the key physiological processes ...
