In the tropical rainforests, which are considered as biomes of the world, you can find more than two-thirds of the world’s plant species. The warm humid environment in which the rainforests grow, is responsible for an enormous variation of plants. Can you imagine how densely the trees of a tropical rainforest are packed? It is said that rain falling on the canopy can take as long as 10 minutes to reach the ground! 1 out of 4 ingredients in our medicine has its origin in the rainforests.
The Amazon jungle is the world’s largest tropical rainforest. Rainforests are located mainly around the equator. They are so dense that due to the competition at ground level for light and food, strange plants which live on the branches of other plants, have evolved or even the plants that strangle large trees to fight for survival are seen in these rainforests. It is impossible to include the list of plants in the rainforest in this article. Rainforests have billions of species of plants, because they are very old. Some rainforests are almost 100 million years old, which means dinosaurs probably lived in them! South American rainforests are home to more than 2,000 different species of butterflies while central African rainforests exhibit more than 8,000 different species of plants. Birds like bats are essential for the pollination in many tropical rainforest plants such as bananas and mangoes. The forests are connected by vines and ferns and mosses grow on the trees. Here is an overview of some of the main types of plants in the rainforest.
Types of Plants in the Rainforest
Carnivorous Plants in the Rainforest: Plants which obtain nutrients from animal matter are known as carnivorous plants. Venus fly trap and the pitcher plant Nepenthes rafflesiana from south east Asia are the best examples of carnivorous plants. Nepenthes rafflesiana grows as high as 30 feet and has pitchers of about 12 inches in length, They have a cavity filled with either sweet or terrible smelling nectar that attracts insects and they are always overcrowded with digested insects! The biggest flower in the world is seen on the trees of Rafflesia, which grow in the Indonesian rainforests. The most amazing fact about the pitcher plants is that they also eat small mammals and reptiles who try to steal the insects from the pitcher.
Strangler Plants in the Rainforest: Stranglers mostly come from the fig family. They are also called ‘killer trees’. The seed starts growing as an epiphyte, high in the trees. Epiphytes are the trees which derive moisture and nutrients from the air and rain and usually grow on another plant. But they are not parasitic on it. The list of epiphytes includes orchids, philodendrons, ferns and bromeliads. The aerial plants have so-called ‘air roots’ and air is the source of nourishment for them. Poison ivy vines have many small aerial roots. The seeds of these plants are borne and transported by birds and monkeys which eat the fig fruits. The seedlings develop long roots down to the ground and start surrounding the host tree. They grow quickly and the growth eventually suffocates the host, resulting in its death. The host tree leaves a huge upright strangler which has a hollow core. This is the best example of how plants adopt themselves to survive in the given specific environment. The strangler fig uses an adult tree as its host so that it doesn’t have to struggle for light and nutrients at ground level.
Lianas in the Rainforest: Ninety per cent of the world’s vine species are found in tropical rainforests. Lianas are climbing vines which are present throughout tropical rainforests. The thick, woody stems of lianas are of various lengths (up to 3,000 ft) and shapes. They need sunlight for survival and so they climb towards light after beginning the life on the forest floor. For this they depend on trees for support. They bind themselves to trees with sucker roots or tendrils. They climb while growing, by winding themselves round the supporting tree’s trunk. They jump to other trees or start wrapping themselves around other lianas, after arriving at the top of the canopy layer of the rainforest. In this way they create a network of vines which provides the shallow-rooted, top-heavy trees, a very strong support. This helps them to survive against strong winds. Rattan palms, philodendron and Strychnos toxifera are some examples of lianas. The deadly poison strychnine is obtained from Strychnos toxifera. Rattans from Asia have thorny stems and they grow as tall as 650 feet (200 m). Baskets, ropes and wicker furniture is made from them.
Plants with Stilt or Prop Roots: Mangroves grow in wet, muddy soil at the water’s edge. They need a good support as there is always the risk of tides and flooding. They develop several aerial pitchfork-like extensions from the trunk which grow downwards. With the help of these stilt roots, they anchor themselves in the soil trapping sediment and acquire the required stability.
Plants with Buttress Roots: Rainforest trees have shallow roots as the soil has maximum nutrients left at the surface level. Therefore the tall trees develop buttressed roots to obtain the required additional support. Such roots grow out from the base of the trunk, sometimes as high as 15 ft above the ground which also help to absorb more nutrients from the soil by covering more area.
Medicinal Plants in the Rainforest: There are thousands of rainforest plants used for medicine.
- Trumpet tree or Cecropia peltata is widely used in traditional medicine in Central and South America. Every part of the tree is useful. The plant is helpful in treating various diseases which include respiratory illnesses and rheumatism.
- Clavillia or Mirabilis jalapa, a perennial herb which is mainly used to kill viruses, bacteria, fungi, and parasites. This plant offers many active compounds like triterpenes, proteins, flavonoids, alkaloids, and steroids.
- Curare or Chondrodendron tomentosum is a large poisonous vine rich in alkaloids which help in muscle relaxation. The alkaloids are also used as an arrow poison. It is used as an anesthesia and also to treat fever, bruises, edema and kidney stones.
- Suma or Pfaffia paniculata is a large vine which spreads on ground with an extensive root system. It is considered a tonic and an adaptogen which helps the body to resist adverse influences of various factors. Suma root is recommended as an appetizer. It also enhances blood circulation, balances blood sugar levels and improves the immune system, muscular system and memory. Suma root is rich in saponin. (up to 11%). Saponins are beneficial in lowering blood cholesterol and they offer many other benefits too.
- Cocoa tree or Theobroma cacao has more than 150 chemicals in its leaves, seeds, fruit, and bark. Various parts of the tree are used to treat anxiety, fever, fatigue, and coughs. Since hundreds of years, the plant is being used to treat kidney stones and cuts and burns, etc. According to recent researches, polyphenols present in chocolate can prevent heart diseases.
- Annatto/Lipstick tree or Bixa orellana has been used for making things like insect repellent or medicines for lowering blood pressure or even for preparing love potions. Recent researches have approved its use in various medicines and beverages or other useful things. The plant is also used to treat snakebites. Bixin are the carotenoids or the plant pigments, present in the oil of the plant which protects against UV rays. The plant is found beneficial in treating heartburn.
Endangered Plants in the Rainforest: Innumerable number of plants in the rainforest are at the verge of extinction. Orchids, rafflesia, some bamboo species, triunia robusta are some of the examples. According to the statistics available, 23 species are extinct in the wild, 151 species are endangered, 274 species are vulnerable and 688 species are rare. These plants are in danger of extinction in the next 10-50 years unless strict action is taken to reverse their decline. Long-term effects of fire, weeds and pests on plants, grazing pressure from domestic stock and animals such as rabbits, changing fire patterns, the spread of weeds, loss of natural habitat through land clearing for pastoral purposes, urban development and agriculture are the main causes of decline of species.
Rainforests are virtual libraries of chemical invention where drugs like quinine, muscle relaxants, steroids and cancer drugs were found. So many new drugs are still to be discovered. Researches are going on to discover effective drugs for AIDS, cancer, diabetes, arthritis and Alzheimer’s, etc. According to the expert’s estimations, we are losing 137 plant, animal and insect species every single day, due to rainforest deforestation, which equates to 50,000 species a year. With the disappearance of the species of the plants in the rainforest, human beings could be deprived of many possible cures for life-threatening diseases.
By Leena Palande
Article Source: buzzle.com