Resource Acquisition and Transport in Vascular Plants

What is essential for the success of plants?

The ability to gather and conserve resources from their environment.

What processes work together to transfer water, minerals, and sugars in plants?

Diffusion, active transport, and bulk flow.

What adaptations were key steps in the evolution of vascular plants?

Adaptations for acquiring resources both above and below ground.

What does xylem transport?

Water and minerals from roots to shoots.

What does phloem transport?

Sugars created in photosynthesis from leaves to roots and growing tissues.

How do natural selection and plant structure relate?

Natural selection has favored taller plants with branching shoots and efficient transport systems.

What is the role of lateral roots?

They grow out from the taproot in search of water and nutrients in the soil.

What is mycorrhizae?

A symbiotic relationship between roots of some trees and soil fungi that helps exploit soil resources efficiently.

What is the main mechanism for short-distance transport in plants?

Diffusion or active transport.

What is the role of selective permeability in plants?

It regulates the movement of substances into and out of plant cells.

What is the function of proton pumps in plant cells?

They create a hydrogen ion gradient that serves as potential energy for transport.

What is cotransport in plant cells?

A mechanism where a transport protein couples the diffusion of one solute to the active transport of another.

What determines whether a plant cell will uptake or lose water?

Osmosis, which is affected by solute concentration and pressure.

What is water potential in plants?

A measurement that combines the effects of solute concentration and pressure, determining the direction of water movement.

What does water potential (Ψ) indicate?

The potential of water to move from one place to another.

What happens to plant cells in a hypotonic solution?

They become turgid (normal) as water enters the cell.

What is the effect of a hypertonic solution on plant cells?

They become plasmolyzed, losing water and shrinking.

What is the significance of root hairs in plants?

They increase the surface area for absorption of water and nutrients.

How does the structure of leaves affect photosynthesis?

Leaf adaptations help acquire light and CO2 more efficiently.

What is the relationship between stem architecture and light capture?

Stem lengths, widths, and branching patterns affect how well plants capture light.

What is the primary function of taproot systems?

To anchor plants and access deeper water and nutrients.

What is the role of transport proteins in plant cells?

They facilitate the movement of solutes across the cell membrane.

What is the relationship between water uptake and water loss in plants?

Plants must balance water uptake from roots and water loss from leaves.

What is the importance of the hydrogen ion gradient created by proton pumps?

It provides energy for solute transport into plant cells.

What is the effect of solute concentration on water movement?

Water moves from areas of low solute concentration to areas of high solute concentration.

What is the significance of the membrane potential in plant cells?

It contributes to the voltage that drives the transport of solutes.

What is the main advantage of having multicellular branching roots?

They enhance the plant's ability to absorb water and nutrients from the soil.

What is the water potential (Ψ) of pure water at sea level and room temperature?

0 MPa

How do solutes affect water potential?

The addition of solutes reduces water potential, making it negative.

What is solute potential (ΨS)?

The solute potential of a solution is proportional to the number of dissolved molecules.

What is pressure potential (ΨP)?

Pressure potential is the physical pressure on a solution.

What is turgor pressure?

Turgor pressure is the pressure exerted by the plasma membrane against the cell wall.

In which direction does water move in relation to water potential?

Water moves from higher water potential to lower water potential.

What happens to a plant cell in a solution with lower solute concentration?

The cell will gain water and become turgid (firm).

What is the effect of negative pressure on water potential?

Negative pressure decreases water potential.

What is the water potential of a 0.1 M sucrose solution?

-0.23 MPa

If root tissue has a water potential of -0.15 MPa, what happens when placed in a 0.1 M sucrose solution?

Net water flow would be from the root tissue into the sucrose solution.

What are aquaporins?

Aquaporins are transport proteins in the cell membrane that facilitate the passage of water.

How do aquaporins affect water movement across membranes?

The more aquaporins a membrane has, the faster the rate of diffusion of water.

What is bulk flow in plants?

Bulk flow is the efficient long-distance transport of fluid, established by a water potential gradient.

Where is water potential highest in relation to a plant?

Water potential is highest in the soil and lowest in the atmosphere around leaf tissues.

What is the relationship between water potential and the movement of water in plants?

A difference in water potential determines the direction of water movement.

What occurs when a plant experiences turgor loss?

Turgor loss causes wilting, which can be reversed when the plant is watered.

What is the water potential of a flaccid cell?

The water potential of a flaccid cell is 0 MPa.

What happens to a plant cell in a hypertonic solution?

The cell will lose water and become plasmolyzed.

What is the water potential of a turgid cell at osmotic equilibrium?

The water potential of a turgid cell is 0 MPa.

What is the significance of a U-shaped tube in measuring water potential?

It demonstrates how water moves from higher to lower water potential across a semipermeable membrane.

What is the initial condition of a cell in pure water?

The initial condition is that the cell has a higher water potential than the surrounding water.

What happens to water movement when the pressure potential increases?

Increased positive pressure raises the water potential.

What is the water potential of a cell in a 0.4 M sucrose solution?

The water potential is -0.9 MPa.

How does water move from roots to shoots in plants?

Water is transported through bulk flow driven by water potential gradients.

What is the effect of adding solutes to a solution on its water potential?

Adding solutes decreases the water potential, making it more negative.

What is the water potential of a cell with ΨP = 0.7 MPa and ΨS = -0.7 MPa?

The water potential (Ψ) is 0 MPa.

What is the primary mechanism that drives bulk flow of water in plants?

Transpiration, which creates negative pressure in the xylem.

What role do roots play in water uptake?

Roots actively take up minerals, creating a lower water potential than the surrounding soil, which drives water into the roots.

What is the transpiration-cohesion-tension mechanism?

It describes how water is pulled upward through the xylem due to negative pressure created by transpiration and the cohesion of water molecules.

How does transpiration affect water potential in leaves?

Transpiration lowers water potential in leaves, generating negative pressure that pulls water up from the roots.

What is the significance of stomata in plants?

Stomata are openings that regulate gas exchange and water loss; about 95% of water loss occurs through them.

How do guard cells function in relation to stomata?

Guard cells control the opening and closing of stomata by changing shape based on turgor pressure.

What environmental factors can increase water loss through stomata?

Sunny, warm, windy, and dry conditions can increase the rate of transpiration.

What adaptations do xerophytes have to reduce water loss?

Xerophytes have small, thick leaves, waxy cuticles, buried stomata, and some open stomata at night to minimize water loss.

What is the role of potassium ions (K+) in guard cells?

Potassium ions regulate turgor pressure in guard cells, causing them to open or close the stomata.

What is the water potential gradient in a plant?

It is the difference in water potential between different parts of the plant, driving water movement from areas of higher potential to lower potential.

What happens to guard cells when they become turgid?

When guard cells are turgid, they bow outward, opening the stomatal pore.

What is the primary factor that triggers stomatal opening at dawn?

Light, along with CO2 depletion and an internal clock in guard cells.

What is the relationship between transpiration and water uptake from the soil?

Transpiration creates a negative pressure that pulls water from the soil into the roots.

What is the effect of cohesion and adhesion on water transport in plants?

Cohesion keeps water molecules together, while adhesion helps water molecules stick to xylem cell walls, facilitating upward movement.

Which part of the plant generally has the most negative water potential?

The cells of the leaf.

What is the role of the xylem in plants?

The xylem transports water and minerals from the roots to the leaves.

What is the primary cause of negative pressure in the xylem?

Transpiration, which pulls water upward through the xylem.

How does the structure of leaves contribute to transpiration?

Leaves have a large surface area and high surface-to-volume ratio, which increases water loss through stomata.

What is the significance of the stomatal density in plants?

Stomatal density is genetically and environmentally controlled, affecting the rate of transpiration.

What happens to guard cells when they lose turgor pressure?

They become flaccid, causing the stomatal pore to close.

What is the primary energy source for the movement of water in the xylem?

Evaporation from the leaves, which does not require ATP.

What is the function of mesophyll cells in relation to transpiration?

Mesophyll cells facilitate gas exchange and contribute to the water potential gradient in leaves.

How does water vapor exit the leaf?

Water vapor diffuses down its water potential gradient and exits through the stomata.

What is the impact of environmental conditions on stomatal behavior?

Environmental conditions such as light and humidity influence the opening and closing of stomata to balance photosynthesis and water loss.

What is the relationship between transpiration and photosynthesis?

Transpiration facilitates nutrient transport and gas exchange, which are essential for photosynthesis.