4 - Campbell Biology

Question

Focusing just on the effects of temperature, would you expect the global distribution of C₄ plants to expand or contract as Earth becomes warmer? Why?

Step-by-Step Solution

Answer

The global distribution of C₄ plants will expand as Earth becomes warmer because alternate modes of carbon fixation have minimized photorespiration in C₄ plants and increased sugar production in hot and arid climates.

Step 1: C 4 photosynthesis

C₄ photosynthesis concentrates carbon dioxide in bundle sheath cells, and it is the most important photosynthetic adaptation.It forms an intermediate four-carbon compound breaking into a 3-carbon compound for the Calvin cycle.

Step 2: Increased CO 2 and global warming effect

Global warming and increased carbon dioxide are concerned with climate change, but that has opposite effects on the quantum production of C₄ photosynthesis.C₄ photosynthesis is more efficient as it utilizes less water and resources.

Step 3: Response of C 4 plants at high temperature

At elevated carbon dioxide levels, C₄ plants photosynthesize more efficiently and are more productive at high temperatures. The plants close stomata to prevent water loss, reduce the availability of CO₂ at higher temperatures, and lock oxygen to increase photorespiration.

 

Thus, plants with C₄ photosynthesis can expand globally due to minimizing photorespiration and increasing sugar production.