Plant Adaptations to the Rainforest

7/28/2019 Plant Adaptations to the Rainforest

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Problems That Rainforest Plants Face

Plants that live in the rainforest have adapted in amazing ways to several verydifficult conditions. This means that the plant has changed something in its"body" or "habits" (the things that it does) to make it easier to survive in difficultconditions. There are several conditions they have had to adapt to. First, the soilof the forest floor is shallow, which means not very deep. Also, the soil of the

rainforest is not very fertile, or easy to grow in. Most of the nutrients, orvitamins and minerals that help plants grow are contained in the living trees ofthe rainforest, not in the soil. The forest floor and understory do not receivemuch light, which also makes it difficult for plants to survive there. Next, is theproblem of very heavy rains which continue over a large part of the year. Finally,many plants of the rainforest are food for animals that live there. This is not aproblem for rainforest animals, but it is one for rainforest plants!

The biggest problem that rainforest plants have to adapt to is the lack of sunlight

in the rainforests lower levels. Plants have adapted to this problem in severalways. Many plants have very large leaves. Large leaves are helpful becausethey have more surface area. The more surface area a leaf has the moresunlight it can absorb. The canopy trees adapt by growing to be 100 feet tall sothat their leaves can grab all available sunlight. Other plants called lianas(climbing woody vines) have adapted by rooting themselves in the soil of theforest floor and growing up the trees until they reach the canopy layer. Still otherplants, such as epiphytes, have adapted by growing directly on the trees trunksand branches in the canopy and understory layers of the rainforest.

How do Plants Adapt to the Rainforest Climate?


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Epiphytes Lianas

An adaptation to the large amounts of rainfall that many rainforest plants have iscalled drip tips. Their leaves are tapered to a sharp point at the end. This allows

water to run off of the leaf quickly. Two additional adaptations to rainfallinclude leaves having a waxy film allowing quick runoff and most leaves alsohave flexible stems which allow water to drip from the leaves to the soil below.There are many other adaptations that rainforest plants have made to theirenvironment. These will be discussed in detail, as we investigate the plants ofthe rainforest!

Drip Tip

Plant Adaptations Listed

1. BarkIn drier, temperate deciduous forests a thick bark helps to limit moistureevaporation from the tree's trunk. Since this is not a concern in the high humidity oftropical rainforests, most trees have a thin, smooth bark. The smoothness of the

bark may also make it difficult for other plants to grow on their surface.

2. Lianas


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Lianas are climbing woody vines that drape rainforest trees. They have adapted tolife in the rainforest by having their roots in the ground and climbing high into thetree canopy to reach available sunlight. Many lianas start life in the rainforestcanopy and send roots down to the ground.

3. Drip TipsThe leaves of forest trees have adapted to cope withexceptionally high rainfall. Many tropical rainforest leaveshave a drip tip. It is thought that these drip tips enable raindrops to run off quickly. Plants need to shed water to avoidgrowth of fungus and bacteria in the warm, wet tropicalrainforest.

4. Buttresses

Many large trees have massive ridges near the base thatcan rise 30 feet high before blending into the trunk. Why dothey form? Buttress roots provide extra stability, especiallysince roots of tropical rainforest trees are not typically as deep as those of trees intemperate zones.

5. Prop and Stilt RootsProp and stilt roots help give support and are characteristic of tropical palmsgrowing in shallow, wet soils. Although the tree grows fairly slowly, these above-ground roots can grow 28 inches a month.

6. EpiphytesEpiphytes are plants that live on the surface of other plants,especially the trunk and branches. They grow on trees totake advantage of the sunlight in the canopy. Most areorchids, bromeliads, ferns, and Philodendron relatives. Tinyplants called epiphylls, mostly mosses, liverworts andlichens, live on the surface of leaves.

7. BromeliadsBromeliads are found almostexclusively in the Americas. Somegrow in the ground, like pineapple,but most species grow on thebranches of trees. Their leaves form a vase or tank thatholds water. Small roots anchor plants to supportingbranches, and their broad leaf bases form a water-holdingtank or cup. The tank's capacity ranges from half a pint to 12gallons or more. The tanks support a thriving eco-system of

bacteria, protozoa, tiny crustaceans, mosquito and dragonflylarvae, tadpoles, birds, salamanders and frogs.


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MangrovesOn tropical deltas and along ocean edges and riverestuaries, trees have adapted to living in wet, marshyconditions. These trees, called mangroves, have wide-

spreading stilt roots that support the trees in the tidal mudand trap nutritious organic matter.

Nepenthes

Pitcher plant vines in the family Nepenthaceae have leavesthat form a pitcher, complete with a lid. Sweet or foul-smelling nectar in the pitcher attracts insects, especially antsand flies, that lose their grip on the slick sides and fall intothe liquid. Downward-pointing hairs inside the pitcher

prevent the insects' escape. The insects are digested by theplants and provide nutrients. Pitcher plants are notepiphytes but climbers rooted in the soil.

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Directions: Use the information from the reading sheet to help you answer thefollowing questions. Write your answers as complete sentences.

1. The main idea of this article is:

a. Plants are food for many of the rainforest animals.

b. Plants have adapted to difficult conditions in the rainforest.c. There is not much light in the rainforest, so it is hard for plants to live.

2. What does adapt mean?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


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3. List the difficult conditions that plants have had to adapt to in the rainforest:

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4. What are four different ways that plants have adapted to lack of sunlight inthe rainforest?______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

5. How do drip tips help plants adapt to the heavy rainfalls in the rainforest?

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Plant Adaptations to the Rainforest

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