CAM Photosynthesis

Definition

CAM photosynthesis, or Crassulacean Acid Metabolism, is a photosynthetic adaptation found in certain plants that allows them to conserve water by opening their stomata at night instead of during the day. This process minimizes water loss in arid conditions, making it particularly advantageous for plants in dry environments. By storing carbon dioxide as malate overnight and using it during the day for photosynthesis, these plants can thrive in extreme conditions while still producing energy efficiently.

5 Must Know Facts For Your Next Test

1. CAM plants typically open their stomata at night to capture carbon dioxide, reducing water loss during the hotter daytime hours.
2. This adaptation allows CAM plants to survive in extremely arid environments where other plants might struggle to obtain enough water.
3. Some well-known CAM plants include succulents like cacti and agave, as well as certain orchids and bromeliads.
4. CAM photosynthesis is different from C4 photosynthesis, although both pathways are adaptations to reduce photorespiration and improve efficiency in hot conditions.
5. The process of storing carbon dioxide as malate overnight allows CAM plants to perform photosynthesis efficiently during the day, even with limited water availability.

Review Questions

• How does CAM photosynthesis help plants adapt to arid environments compared to traditional photosynthesis?
  • CAM photosynthesis enables plants to adapt to arid environments by opening their stomata at night instead of during the day. This adaptation significantly reduces water loss, which is crucial in dry conditions. While traditional photosynthesis typically involves daytime stomatal opening, leading to potential dehydration, CAM plants effectively store carbon dioxide as malate overnight, allowing them to utilize this stored carbon during the day when they keep their stomata closed.
• Discuss the advantages and disadvantages of CAM photosynthesis in comparison with C4 photosynthesis.
  • CAM photosynthesis offers advantages such as enhanced water conservation and survival in extreme drought conditions. However, it typically results in slower growth rates compared to C4 photosynthesis, which is more efficient under high light and temperature conditions. While C4 plants can quickly fix carbon dioxide and thrive with higher productivity, CAM plants are better suited for areas where water availability is highly limited. The trade-off between efficiency and water conservation defines the ecological niches these two pathways occupy.
• Evaluate how understanding CAM photosynthesis can influence agricultural practices in regions facing water scarcity.
  • Understanding CAM photosynthesis can greatly influence agricultural practices by guiding the selection of crops that are better suited for water-scarce regions. By utilizing plants that employ this water-conserving pathway, farmers can improve crop resilience against drought and reduce irrigation needs. Additionally, breeding programs could focus on enhancing CAM characteristics in important food crops, potentially increasing agricultural productivity while minimizing environmental impacts associated with water use in farming.

Related terms

Stomata: Small openings on the surface of leaves that allow for gas exchange; they open and close to regulate water loss and carbon dioxide intake.

Photorespiration:

A wasteful process that occurs when the enzyme RuBisCO oxygenates RuBP, leading to a decrease in photosynthetic efficiency and an increase in carbon loss.

C4 Photosynthesis:

A photosynthetic pathway that enhances carbon fixation by initially converting carbon dioxide into a four-carbon compound, allowing plants to minimize photorespiration.