Atmospheric CO₂ has been increasing rapidly since the late 1800s, largely due to human activities. Recall that CO₂ enters leaves through stomata and can then be used for photosynthesis. However, transpiration occurs as a result of water evaporating through stomata.
How have plants responded to elevated CO₂ levels?
One prediction of global climate change is that there will be an increase in periods of drought in some regions. Given the data just presented, will plants be more or less likely to survive periods of drought as they are exposed to rising CO₂ levels?

Verified step by step guidance

1. Understand the role of stomata: Stomata are small openings on the surface of leaves that allow for gas exchange. CO2 enters through stomata for photosynthesis, while water vapor exits during transpiration.
2. Consider the effect of elevated CO2 levels: Higher CO2 concentrations can lead to partial closure of stomata, reducing water loss through transpiration while still allowing sufficient CO2 uptake for photosynthesis.
3. Analyze the impact on drought survival: With stomata partially closed, plants may conserve water more effectively, potentially increasing their ability to survive during drought conditions.
4. Evaluate the balance between photosynthesis and water conservation: While reduced transpiration helps conserve water, it is crucial that plants maintain adequate CO2 uptake for photosynthesis to sustain growth and energy production.
5. Predict plant adaptation strategies: In response to rising CO2 levels and increased drought, plants may evolve or adapt mechanisms to optimize stomatal function, balancing CO2 uptake and water conservation to enhance survival.

Key Concepts

Photosynthesis

Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy, using carbon dioxide and water to produce glucose and oxygen. Elevated CO2 levels can enhance photosynthesis, potentially increasing plant growth and productivity. Understanding this process is crucial to predicting how plants might respond to changing atmospheric conditions.

Stomatal Function

Stomata are small openings on the surfaces of leaves that regulate gas exchange, allowing CO2 to enter for photosynthesis and water vapor to exit during transpiration. Plants may adjust stomatal density or opening size in response to elevated CO2 levels, which can affect their water use efficiency and ability to cope with drought conditions.

Transpiration

Transpiration is the process of water movement through a plant and its evaporation from aerial parts, primarily leaves. It plays a critical role in nutrient transport and temperature regulation. In the context of rising CO2 levels, understanding transpiration helps assess how plants might balance water loss with CO2 uptake, influencing their survival during drought periods.