Evidence indicates that plants increase the number of stomata in their leaves as atmospheric CO₂ levels decline. Increasing the number of stomata per unit surface area should have the effect of doing which of the following?
1)increasing dehydration of leaf tissues
2)decreasing dehydration of leaf tissues
3)countering the effect of declining CO₂ on photosynthesis
4)reinforcing the effect of declining CO₂ on photosynthesis
5)decreasing the O₂ content of air next to the leaves lower than it would otherwise be
6)increasing the O₂ content of air next to the leaves higher than it would otherwise be

Question

Quizplus · Accepted Answer

Increasing the number of stomata per unit surface area would decrease dehydration of leaf tissues as it increases the surface area for gas exchange, allowing for more efficient uptake of CO2 and release of O2. This counters the effect of declining CO2 on photosynthesis by promoting more efficient gas exchange. It would also increase the O2 content of air next to the leaves higher than it would otherwise be, as efficient gas exchange would result in a higher concentration of O2 in the surrounding air. Option 1 is incorrect as it suggests that increasing the number of stomata would lead to increased dehydration, which is the opposite of what occurs. Option 4 is incorrect as it suggests that increasing stomata numbers would reinforce the negative effect of declining CO2 on photosynthesis, whereas it actually counters it. Option 5 is incorrect as it suggests that increasing stomata numbers would decrease the O2 content of air next to the leaves, which is also incorrect as more efficient gas exchange would result in higher O2 concentration. Option 2 is incorrect as it suggests that decreasing stomata numbers would decrease dehydration, but the question is asking about the effect of increasing stomata numbers.

Evidence Indicates That Plants Increase the Number of Stomata in Their