Mesophyll

Definition

Mesophyll is the inner tissue of a leaf, primarily responsible for photosynthesis. It is located between the upper and lower epidermis and is rich in chloroplasts, which allow plants to convert sunlight into energy. The mesophyll is typically divided into two layers: palisade mesophyll, which is tightly packed and maximizes light absorption, and spongy mesophyll, which has more air spaces to facilitate gas exchange.

5 Must Know Facts For Your Next Test

1. The palisade mesophyll cells are elongated and arranged closely together, maximizing their exposure to sunlight for efficient photosynthesis.
2. Spongy mesophyll has a looser arrangement of cells with large air spaces that allow for better gas exchange between the leaf and the atmosphere.
3. Mesophyll contains a high concentration of chlorophyll, which is crucial for capturing light energy during photosynthesis.
4. The arrangement of mesophyll in leaves can vary between different plant species, influencing their ability to photosynthesize in various light conditions.
5. Water transport through the mesophyll occurs via transpiration, which helps maintain the flow of nutrients and gases necessary for plant health.

Review Questions

• How does the structure of mesophyll contribute to its function in photosynthesis?
  • The structure of mesophyll is specifically designed to enhance its role in photosynthesis. The palisade mesophyll, with its tightly packed, elongated cells, captures maximum sunlight due to its arrangement just below the upper epidermis. Meanwhile, the spongy mesophyll, with its loose cell structure and air spaces, facilitates gas exchange by allowing carbon dioxide to diffuse into the leaf while oxygen exits. This structural arrangement ensures that light absorption and gas exchange are optimized for efficient photosynthesis.
• Evaluate how environmental factors can influence the efficiency of mesophyll in photosynthesis.
  • Environmental factors such as light intensity, temperature, and humidity significantly impact the efficiency of mesophyll in photosynthesis. For example, higher light intensity generally increases the rate of photosynthesis up to a certain point due to more photons being available for chlorophyll absorption. However, extreme temperatures can damage chloroplasts or inhibit enzyme function involved in photosynthesis. Additionally, humidity levels affect stomatal opening; if stomata are closed due to low humidity, gas exchange is restricted, reducing carbon dioxide availability for the mesophyll cells.
• Synthesize information about mesophyll with other leaf structures to explain their interdependence in plant health.
  • Mesophyll works in conjunction with other leaf structures like stomata and epidermis to ensure overall plant health and efficiency. The stomata allow for gas exchange, providing carbon dioxide necessary for the mesophyll's photosynthetic activity while also releasing oxygen as a byproduct. The epidermis protects against water loss and physical damage while supporting stomatal function. Together, these structures create a synergistic relationship where efficient gas exchange via stomata enhances the photosynthetic capacity of mesophyll, ultimately contributing to the plant's ability to thrive in its environment.

Related terms

Chloroplast: An organelle found in plant cells that contains chlorophyll and is the site of photosynthesis.

Stomata: Small openings on the surface of leaves that allow for the exchange of gases, such as carbon dioxide and oxygen.

Epidermis: The outer layer of cells covering the leaf, providing protection and helping to minimize water loss.