Why wheat is a C3 plant?

Answer 1

Wheat has evolved as a C3 plant because it naturally occurs in temperate regions of the world, where the temperature is mild.

In areas of the world where the temperature is high, plants with metabolisms such as C4 and CAM begin to dominate, as C3 plants are less energy efficient at high temperatures.

This is because rubisco, the key protein in fixing carbon dioxide in C3 plants, is induced to dissipate the products of photosynthesis by high temperatures (a process known as photorespiration). This is a wasteful procedure that can lead to net loss of carbon from the plant.

However, as C4 and CAM mechanisms for carbon dioxide fixation also require more energy, C3 plants dominate in temperate regions (and make up the majority of plant life on Earth).