Edited Invalid date
25.3 Transport Mechanisms in Plants
The upward movement of water in flowering plants is influenced by the properties of water.
The sequence of events for the movement of water in xylem and sucrose in phloem should be listed.
Flowering plants are able to live in a terrestrial environment.
The leaves are positioned to catch the rays of the sun because they are held aloft by the stem.
Water is absorbed by the roots when carbon dioxide enters the leaves.
Water must be moved from the roots to the leaves.
The strong-walled, non living cells of Xylem give trees much-needed internal support.
There are two types of conducting cells in Xylem.
Cells are being conducted in xylem andphloem.
The xylem and phloem cells form a pathway for the movement of water and carbohydrates in a plant.
The xylem and phloem are continuous from the roots through the stem to the leaves.
The water potential is higher at the roots.
Water potential is lower at the leaves.
The pits allow water to pass from one tracheid to another.
A hollow line from the roots to the leaves is formed by vessel elements.
The process of photosynthesis results in sugars, which are used as a source of energy and building blocks for other organic molecule throughout a plant.
Roots buried in the soil need a source of energy to carry on their cellular metabolism.
phloem consists of two types of cells, sieve-tube members and companion cells.
The sieve plates have a lot of pores and strands of cytoplasm extend from one sieve-tube member to another.
There are no nuclei in Sieve-tube members.
The mechanisms by which material moves from one part to another is not told by knowing how the plants are structured.
Experiments have been done to determine how water and minerals rise to the top of trees in xylem and how organic nutrients move in the opposite direction.
In living systems, water diffuses freely from the area of higher concentration to the area of lower concentration.
Water always flows from the area of higher water potential to the area of lower water potential when described by plant scientists.
The concept of water potential involves water pressure and osmotic pressure.
In Section 6.1, you learned that potential energy is stored.
Potential energy can be found in an object's position, such as that of a boulder at the top of a hill, or in chemical bonds.
The energy of motion is called kruin energy.
A boulder rolling down a hillside is showing a lot of energy, as well as an enzyme reaction that breaks a bond, converting ATP toADP and releasing energy in the process.
The water at the top of a waterfall has a higher water potential than the water at the bottom.
Water moves from a region of higher water potential to a region of lower water potential.
Water moves from a higher pressure area to a lower pressure area.
Pressure potential is the best explanation of the movement of sap in xylem and phloem.
The presence of solutes restricts the movement of water because it interacts with solutes.
The effects of solute concentration can be counteracted by increasing the water pressure.
The situation is common in plant cells.
A plant cell has a strong cell wall that allows water pressure to build up.
When the pressure potential inside the cell balances the osmotic potential outside the cell, the flow of water in and out is the same.
Plants depend on turgor pressure to maintain their turgidity.
The plant droops because the cells have insufficient turgor pressure.
Water flows from higher water potential to lower water potential.
Water enters the cells because they have a lower water potential.
When the water potential is equal inside and outside the cell, equilibrium can be achieved.
The plant is no longer floppy.
The chemical properties of water are important.
The hydrogen bonding between water molecule allows water to fill xylem cells.
The root xylem tissue has high concentrations of minerals.
"leak" xylem sap is the difference between this solute concentration.
Water is being drawn out from the leaves during the day, so root pressure isn't as obvious.
At night, water enters the roots, but it doesn't evaporate at the surface of the leaves.
This results in a phenomenon called guttation.
The root pressure is the cause of the "dew" effect this morning.
Positive pressure potential is caused by the entrance of water into root cells.
Guttation is caused by root pressure.
Guttation is often mistaken for early morning dew.
Water entering the xylem must be transported against gravity to all parts of the plant.
Transporting water can appear to be difficult for plants such as redwood trees, which can reach almost 300 feet in height.
Expenditure of energy by the plant is not required in the model of xylem transport outlined in Figure.
There is a higher water potential in the soil and a lower water potential in the plant.
Osmosis will move water into the root.
The root pressure created by all of the water entering roots is helpful for the upward movement of water but not enough to get it all the way up to the leaves in a tall tree.
The water molecule escaping from the mesophyll and into the air can be seen on the top of the tree.
There is a chain of water molecule that is escaping.
The movement of water through xylem is similar to drinking water from a straw.
A chain of water molecule is drawn upward by the pressure on the straw.
Water sticks together with hydrogen bonds.
There is a constant tugging or pulling from the top.
The water column is pulled upward from the leaf, stem, and roots as transpiration occurs.
Unlike other plant cells, xylem vessels have low resistance for the movement of water.
Over a long period of time, a plant loses a large amount of water.
Most of the water taken up by roots is lost at the leaves.
During the growing season, a single corn plant loses between 135 and 200 liters of water.
The effects of plant transpiration on climate are enormous.
The Amazon rain forest receives an estimated one-half to three-quarters of its precipitation from water vapor of transpiring plants.
Plants cool themselves and their environments by being able to evaporate large amounts of water from their surfaces.
The mist is coming from a tropical rainforest.
Plants create water vapor by releasing enormous amounts of water.
Water vapor is an important source of precipitation, and the process of evaporative cooling is responsible for cooling the plants.
The way water is transported in plants has consequences.
The stomata closes when a plant is under water.
Many plants are unable to photosynthesize because carbon dioxide cannot enter the leaves.
Photosynthesis requires an abundant supply of water to allow carbon dioxide to enter.
The guard cell's radial expansion is restricted because of the cellulose microfibrils in the walls, but the outer walls can be expanded.
When the outer walls expand, they pull out from the region of their attachment.
When the entrance of K+ leads to the entrance of water, a stoma opens.
The exit of K+ and the exit of water cause a stoma to close.
In other words, active transport of K+ into guard cells causes water to follow by osmosis.
H+) accumulate outside guard cells as K+ moves into them.
H+ is transported to the outside of the cell by a protons pump.
This establishes a channel that allows K+ to enter.
The blue-light component of the sun regulates the opening and closing of the stomata.
When the concentration of CO2 goes up, the pump in the guard cells could be shut down.
Abscisic acid can cause the stomata to close.
Water is conserved.
Plants respond to the presence of sunlight in the daytime and the absence of sunlight at night when they are kept in the dark.
The implication is that the internal clock is keeping time.
There are areas of intense investigation regarding the rhythms and biological clocks.
The opening and closing of stomata can be influenced by temperature, humidity, and stress.
Mosses are ancient plants with no veins.
Water, minerals, and the products of photosynthesis all move from one cell to the next.
There were many challenges for survival as plants evolved.
Plants have evolved to acquire water and minerals.
The shoot system and root system became separated as plants grew taller, and other systems evolved for long-distance travel.
The tissue that transfers the products of photosynthesis is called phloem.
Young leaves, fruit, and roots are some of the areas where sugar can be found.
The inner bark of plants is made up of phloem.
Page 469 explains why girdling a tree will cause the tree to die.
The lower half of the tree's supply of sugar is cut off if a strip of bark is removed.
Water is in xylem and phloem does not move solely upward or downward.
The phloem is moving from source to sink.
Radioactive studies with carbon 14 have shown that phloem transports organic nutrients from source to sink.
The liquid in the phloem is mostly water and sugar, but there are other substances that travel in the phloem as well.
Plant scientists have conducted many experiments to prove that what starts at a source can end up in a sink.
Sugar is transported from the cells in the leaf mesophyll into the sieve tubes of the phloem.
phloem is a continuous line throughout the plant.
Sugar is cotransported with hydrogen ion that are moving down their concentration.
H+ ion are pumped into the mesophyll cell so they can be co-transported.
Sugars are dissolved in water to form phloem.
The water is pulled in through the sieve tubes.
Positive pressure moves the phloem toward the sink.
High concentrations of sugar in the sieve tubes cause water to flow.
As water flows in, there is an increase in positive pressure.
The pressure-flow model got its name because phloem has been measured moving at a rate of 1 m an hour.
When the sugar arrives at the root, it is transported out of sieve tubes into the root cells.
The sugar is used for metabolism.
The high concentration of sugar in the root cells causes water to follow by Osmosis, where it is reclaimed by the xylem tissue.
Storage roots and stems, such as carrots, beets, and potatoes, are examples of sources of sugar during winter or periods of dormancy.
The high pressure of phloem has resulted in an interesting observation of insects.
Aphids have a mouthpart called a stylet that can penetrate a stem and open a sieve tube.
The high-pressure solution is forced through the insect's stomach and ends up on the rear end.
The page protects the insects.
Scientists take advantage of the natural phloem-tapping system by anesthetizing a drinking aphid, removing its body, and using the inserted stylet to collect phloem for analysis.
The phloem would clot if the researcher put a needle in it, but the aphids have an anticlotting property in their saliva that prevents the clot from forming.
Acquiring a plant.
A stylet is a needlelike mouthpart that aphids use to remove food from phloem.
After the phloem has passed through the aphid's body, it appears as a droplet.
phloem can be used for collection and analysis when an insect is cut away from its stylet.
A plant's dry weight is made up of carbon, hydrogen, and oxygen.
Minerals are taken up by the roots.
The use offertilizer can help avoid mineral deficiencies.
Sand, silt, and clay are the three types of soil particles.
Water and air spaces are retained in loam, which contains about equal proportions of all three types.
The humus contributes to the texture of the soil.
Water, along with minerals, can enter a root by passing between the porous cell walls until it reaches the Casparian strip.
Water can enter root hairs and pass through the cells of the cortex to reach xylem.
There is a CHEMiosmotic mechanism.
This causes positive ion to flow into the cells.
When H+ moves along its concentration gradient, negative ion are carried across the membrane.
Plants have a number of ways to get the food they need.
The root gives the fungus sugars and amino acids.
Plants have a system that transports water and minerals from the roots to the leaves.
The sugar is transported in the opposite direction.
xylem and phloem are included in the cardiovascular tissue.
In xylem, vessels composed of elements aligned end to end form an open line from the roots to the leaves.
This doesn't contribute much to xylem transport.
Most of the water taken in by a plant is lost through transpiration.
When there is plenty of water, the stomata remain open, allowing carbon dioxide to enter the leaf.
The guard cells stretch because of theibrils in their walls.
Water enters the guard cells after the K+) enters.
A high CO2 level may signal the close of the stomata.
Abscisic acid is produced by leaves.
The effects of girdling a tree on phloem was an early observation.
In phloem, sieve tubes composed of sieve-tube members aligned end to end form a continuous line from the leaves to the roots.
The strands of cytoplasm extend through sieve plates from one member to the other.
A sink can be at the roots or any other part of the plant.
Pick the best answer for the question.
A reduction in the concentration of the element is considered essential to plant growth.
K+ is attracted by negatively charged clay particles.
The strip affects how water and minerals move.
Nitrogen is reduced by Nitrogen-fixingbacteria.
The plant needs a supply of oxygen at night.
The plant requires a supply of carbon dioxide during the day.
They are the properties of water.
They create a negative pressure.
It is removed by the source after it enters the sieve tubes.
phloem content always flows from the leaves to the root according to the pressure-flow model.
The video is called BioNow.
Discuss how the xylem is involved in the video.
You are a camp counselor and you ask your kids to put white carnations in the water with blue food coloring.
An experiment to determine whether copper, nitrogen, orphosphate is essential for plant growth.
Let us know if the results are possible.
Review flashcards and saved quizzes
Getting your flashcards
You're all caught up!
Looks like there aren't any notifications for you to check up on. Come back when you see a red dot on the bell!
Privacy & Terms