Cacti survive well in dry climates because they have adapted to the intense heat and arid conditions. These kinds of plants are called xerophytes, and usually have no leaves in order to conserve water. They have a shallow root system that extends out from their base like a radius, which can catch and absorb a maximum amount of water when it rains. These plants depend on their outer layers of skin to perform photosynthesis and produce food so it can survive.
They have adapted to live in the desert. Thick, waxy skins prevent water loss, for example. The spines, which keep away desert dwelling animals, also prevent water loss through transpiration. Wide spreading roots help cacti to suck up as much water and minerals as possible.
Cactus and many other succulents (though not all) have evolved an interesting variation on photosynthesis that makes them more efficient with water usage. For all plants, there is a tradeoff between opening their pores for gas exchange, which is necessary for photosynthesis, and loosing water (as they open their pores to let in CO2, water also escapes). So one adaptation to deal with this is what is known as Crassulacean Acid Metabolism (or CAM photosynthesis). CAM plants open their pores (stomata) at night, when the temperatures are not as high and evaporation rates are lower, and store CO2 as a 4 carbon molecule which is then processed during the day. Many cactus plants have CAM photosynthesis.
Click here to cancel reply.
Sorry,At this time user registration is disabled. We will open registration soon!
Don't have an account? Click Here to Signup
© Copyright GreenAnswers.com LLC