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? In the year 1915, the stomatal conductance of oak was approximately how many times higher than that of pine?
How about in the year 2010?

Verified step by step guidance

1. Understand the relationship between stomatal conductance and CO2 levels. Stomatal conductance refers to the rate at which CO2 enters and water vapor exits through the stomata. Elevated CO2 levels can lead to changes in stomatal conductance as plants adjust to optimize photosynthesis while minimizing water loss.
2. Research historical data on stomatal conductance for oak and pine trees. This involves looking at scientific studies or databases that have recorded these values over time, particularly focusing on the years 1915 and 2010.
3. Compare the stomatal conductance values for oak and pine in 1915. Calculate the ratio of oak's stomatal conductance to pine's stomatal conductance to determine how many times higher it was.
4. Repeat the comparison for the year 2010. Again, calculate the ratio of oak's stomatal conductance to pine's stomatal conductance to see how the relationship has changed over time.
5. Analyze the results to understand how plants have responded to elevated CO2 levels. Consider factors such as changes in stomatal density, size, and conductance, and how these adaptations might affect the plant's water use efficiency and photosynthetic capacity.

Key Concepts

Stomatal Conductance

Stomatal conductance refers to the rate at which CO2 enters and water vapor exits through the stomata of plant leaves. It is a crucial factor in photosynthesis and transpiration, influencing how plants respond to environmental changes such as elevated CO2 levels. Variations in stomatal conductance can affect plant water use efficiency and growth.

Photosynthesis

Photosynthesis is the process by which plants convert light energy into chemical energy, using CO2 and water to produce glucose and oxygen. Elevated CO2 levels can enhance photosynthesis by providing more substrate for the process, potentially leading to increased plant growth. However, this can also affect stomatal behavior and water use efficiency.

Transpiration

Transpiration is the process of water vapor loss from plant leaves through stomata. It plays a vital role in plant water regulation and nutrient transport. Elevated CO2 levels can lead to reduced stomatal opening, decreasing transpiration rates, which may improve water use efficiency but also impact cooling and nutrient uptake in plants.