91Ó°ÊÓ

Scientists on a new project to restore a damaged salt marsh are investigating several plants that could be introduced. Plant X is considered a possible candidate. Before the decision is made, the following data are examined. Assume that the contribution of gravity and matric potential are negligible and can be ignored. Recall that the overall water potential for a system is represented by the equation: \(\Psi\) system \(=\Psi\) total \(=\Psi_{\mathrm{S}}+\Psi_{\mathrm{P}}+\Psi \mathrm{g}+\Psi \mathrm{m}\) overall \(\Psi\) of the soil: \(-2.1\) MPa solute potential of the plant’s cell contents: -0.12MPa pressure potential \((\Psi p)\) of the plant’s cells: -2.3 MPa Is Plant X a good candidate for introduction to the salt marsh? a. Yes, because the overall water potential of the plant is less negative than the water potential of the soil. b. No, because the overall water potential of the plant is less negative than the water potential of the soil. c. Yes, because the overall water potential of the plant is more negative than the water potential of the soil. d. No, because the overall water potential of the plant is more negative than the water potential of the soil.

Step by step solution

01

- Understand the Water Potential Equation

The overall water potential ( \( \Psi \text{ system} \)) of a system is given by the equation: \( \Psi \text{ total} = \Psi \text{ S} + \Psi \text{ P} + \Psi \text{ g} + \Psi \text{ m} \). Given that the contributions of gravitational potential (\( \Psi \text{ g} \)) and matric potential (\( \Psi \text{ m} \)) are negligible, the equation simplifies to: \( \Psi \text{ total} = \Psi \text{ S} + \Psi \text{ P} \).

02

- Calculate the Total Water Potential for the Soil

Read the given data: the water potential of the soil is \(-2.1 \text{ MPa}\). Since it's explicitly provided as \( \Psi \text{ soil} = -2.1 \text{ MPa} \), no further calculation is necessary.

03

- Calculate the Total Water Potential for Plant X

Using the given solute potential (\( \Psi \text{ s} \)) and pressure potential (\( \Psi \text{ p} \)) values for Plant X: \( \Psi \text{ s (Plant)} = -0.12 \text{ MPa} \) and \( \Psi \text{ p (Plant)} = -2.3 \text{ MPa} \), we can compute the total water potential for Plant X as: \( \Psi \text{ total (Plant)} = \Psi \text{ S(Plant)} + \Psi \text{ P(Plant)} \) \[ \Psi \text{ total (Plant)} = -0.12 \text{ MPa} + (-2.3 \text{ MPa}) \] \[ \Psi \text{ total (Plant)} = -2.42 \text{ MPa} \]

04

- Compare the Water Potentials

Compare the total water potential of the plant and the soil: \( \Psi \text{ total (Plant)} = -2.42 \text{ MPa} \) versus \( \Psi \text{ soil} = -2.1 \text{ MPa} \). Since \( -2.42 \text{ MPa} \) (Plant) is more negative than \( -2.1 \text{ MPa} \) (Soil), water will move from the soil into the plant because water moves from higher (less negative) to lower (more negative) water potential.

05

- Conclusion

Based on the comparison, the plant can effectively take up water from the soil. Therefore, looking at the options: (c) Yes, because the overall water potential of the plant is more negative than the water potential of the soil, is correct.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

solute potential

Solute potential, also known as osmotic potential, is a key concept in understanding water potential in plants. It's represented by \(\Psi_S\) and refers to the effect of dissolved substances in water. In a plant cell, solute potential is typically negative because solutes reduce the free energy of water, making it less likely to move.

Here's a simple way to think about it: when there are more solutes (like salts or sugars) inside a cell, the water potential decreases because water is attracted to these solutes. It essentially 'pulls' water into the area with higher solute concentration.

Therefore, when comparing water potentials in different areas, remember that a more negative solute potential means a stronger pull for water. For instance, in the salt marsh experiment, Plant X has a solute potential of -0.12 MPa, helping us calculate its overall water potential.

pressure potential

Another important aspect of water potential is pressure potential (\( \Psi_P \) ). This is the physical pressure exerted on or by the water within plant cells. Unlike solute potential, pressure potential can be positive or negative.

In turgid cells, where the cell is swollen with water, the pressure potential is usually positive, indicating that water is being pushed against the cell wall, creating turgor pressure. However, in the case of Plant X, the pressure potential is -2.3 MPa, which means the cells are under negative pressure or tension, typically observed in water-stressed plants.

Understanding how pressure potential contributes to the total water potential helps in predicting water movement. For our salt marsh case, combining it with solute potential gives us the total water potential to make an informed decision about the plant's suitability for the environment.

salt marsh restoration

Salt marsh restoration is an ecological effort aimed at reviving damaged or degraded salt marshes to their natural state. These ecosystems are crucial for coastal protection, carbon storage, and providing habitat for wildlife. However, their restoration involves understanding plant-water relations, among other factors.

When selecting plants for restoration, scientists look for species that can efficiently uptake water despite saline conditions. This involves analyzing water potential parameters like in the case of Plant X. A plant with a more negative total water potential than the soil can absorb water effectively from the salty soil, making it a good candidate for restoration projects.

Such detailed evaluations ensure that the introduced plants not only survive but thrive, helping to bring back the essential functions of salt marshes.