What exactly is transpiration?

Question

I know transpiration is the loss of water in a plant. However, in my book, it states that the rate of transpiration in desert plants are low. I thought desert plants would transpire faster since they are exposed to sunshine and heat. Can anyone explain? thanks!

Answer 1

Cactus do not have delicate leaves so have less surface area. They have heavy wax coats to block evaporation except through pores called stomata. Transpiration is regulated by closing the stomata but other wise is passive. So if the pores are open the plant is losing water.

The spines provide shade or filter the light reaching the plant so the plant is protected from some heat & UV. But most importantly the stomata open only in cool night air unlike most plants that open during the day. These details combine to drastically lower the water loss and cause a problem. Because they do not have access to CO2 in the day since their stomata are closed they have a different form of photosynthesis called crassulacean acid metabolism, CAM, so they can use light but keep stomata closed during the day's heat.

http://www.nps.gov/arch/naturescience/ca...

Answer 2

its like a car, bike, train, or plane. anything that takes u somewhere