If plants in the rainforest and desert were able to share what they each have in abundance, rainforests would be less lush and deserts greener. Plants in the rainforest compete to reach the sun with broad leaves and tall stems, while desert plants evolved to store water. Most rainforests receive more than 100 inches of rain annually, while deserts barely collect 10 inches of precipitation a year in a good year, with periods of droughts frequently occurring. These drastic differences caused the plants within these two biomes to develop and adapt to their distinctive living conditions in different ways to help them thrive.
TL;DR (Too Long; Didn't Read)
Plants in the rainforest compete to reach the sun with broad leaves and tall stems, while desert plants evolved to store water.
Because deserts receive so little rain per year, plants had to adapt to these drought-like conditions to survive. Not as much grows in deserts because the plants must withstand long periods without rain, but what does grow there usually thrives. Some desert plants die back each year, only to return after spring storms hit. Deserts support plant life that includes succulents, small-leafed trees, annual plants and drought-tolerant bushes. Most all the plants in the desert have small, tiny, leaves, as sun is plentiful and readily available.
A lot of the plants in the rainforest climb to reach the sun, while some on the floor of the forest – heterotrophs – evolved as non-photosynthetic plants that don’t have the sun requirements of other plants. Air plants, or epiphytes, evolved to live high up on trees to gain moisture and nutrients with less competition, while woody vines, or lianas, climb rapidly up trees to areas where the canopy is open. Stranglers start out as air plants, but once up high in the trees, they send roots down to the forest floor in search of nutrients. Rainforests produce a variety of trees, bromeliads, climbers, stranglers and plants that don’t require as much sun.
Desert Survival Mechanisms
Desert plants evolved to get as much water and nutrients out of their environments as possible. Thorny bushes and plants protect against water predators, while mesquite bushes and trees developed long taproots – up to 30 feet – to retrieve as much water as possible from supplies beneath the ground. Other desert plants have shallow root systems that spread wide beneath the ground to collect as much water as possible when it rains. Succulents thrive because they store water within their fleshy innards for periods of drought. Some annual and perennial plants don’t produce plants every year, as their hard-cased seeds can survive through many seasons of drought before the conditions are right for their growth.
Thriving Rainforest Plants
With rainfall that occurs regularly throughout the year, many plants grow in a rainforest, and competition is steep for the sun and nutrients in the ground. Like deserts, rainforest soils don’t have a lot of nutrients because of how fast nutrients cycle, and thick three-layered canopies prevent the sun from reaching the lower levels of the forest. Plants in a rainforest evolved to have broad waxy leaves that easily shed rainwater for respiration purposes, but open wide to collect energy from the sun. Once a tree reaches above the canopy of the rainforest, its leaves become smaller and more efficient. Many rainforest plants have shallow roots because they focus on collecting nutrients as opposed to water.