In fall, leaves may change from green to yellow or red. Explain in your own word
ID: 59636 • Letter: I
Question
In fall, leaves may change from green to yellow or red. Explain in your own words what is happening inside the leaf with regard to plant pigments. [3 pts]
Plants are categorized as C3, C4, or CAM plants depending on the type of photosynthesis they perform. Which type of plant performs best in a hot dry climate? Explain your answer. [2 pts]
Hypothesize how global climate may affect photosynthesis in land plants? In optimum growing conditions where resources (e.g. water, nutrients) are unlimited, which type of plant (C3, C4 or CAM is most likely to benefit from global warming? Explain your answer in terms of carbon fixation.
Explanation / Answer
* Plants change their leaf color during fall. There is not enough sunlight during winters, so plants slowly down regulate photosynthesis. The bright green colour fades away, expoisng the accessory pigments. These pigments are always present, but are masked by the bright green colour when cholorophyll is abundant
* CAM plants are adapted to perform photosynthesis in hot dry desert climates. These plants fix CO2 during night, they store the oxaloacetic acid required for CO2 fixing, in large vacuoles. This makes their stomate open at evening, when temperatures go down, and thus avoid water loss, but allow exhange of CO2.
* When resources are unlimited, or abundance of resources available, all the three types of plants are benefited, but CAM plants are most benefited. However, global warming leads to increased temperatures which makes it hostile for C3 and C4 plants to photosynthesize.