poisonous-plantsPlants have evolved to protect themselves against potential threats of herbivores. They have developed many adaptations including the production of poisonous substances. These poisonous substances can cause itching, vomiting, diarrhea, and even death. The poisonous plants play an important role in nature. Let’s dig in deep!

Why Plants Carry Poison?

herbivoryThe first question that everyone will probably ask about poisonous plants is, why do plants produce poison? Because we think of plants as good creatures that are a primary food source for animals. So why do they want to harm the animals? There are some reasons behind it, let’s discuss them.

The main reason for the plants to produce poisonous substances is to get protection from herbivores. Herbivores (plant eaters) consume the plants to survive. Suppose some herbivores start to eat one plant together, they may consume the whole plant. As a result, the plant will die completely. So, some plants have evolved to produce poisonous substances in them. They produce varying amounts of poison to protect them against herbivory when they are consumed more than an average.

Sloth is hanging on a mangrove tree

Some plants carry permanent poison to protect themselves from herbivores. For example, the leaves of mangrove trees are poisonous to many herbivores. However, a few herbivores can digest these poisonous leaves, e.g. sloths. Being poisonous means only a few species of animals can eat these leaves which helps mangroves to survive while providing food to limited herbivores.

Uses of Poisonous Plants

Poisons of the plants are of course harmful to animals and humans. But, they are also used by scientists in the preparation of medicines and other applications.

  • Medical Uses: Traditionally, a plant called Belladonna has been used to relieve muscle spasms due to its analgesic properties. Another plant, Digitalis, has provided the first remedy for cardiac arrest, which helped in strengthening the heartbeat.
  • Cosmetics: Castor oil is widely used by the cosmetic industry due to its moisturizing properties. The castor oil is extracted from very toxic castor seeds. First, it is filtered from toxic substances and then it is used for cosmetics.
  • Hunting: People have used the poison of the ‘Buckeye’ plant for hunting fish.

Most Poisonous Plants on Earth

Aconitum Napellus

Aconitum-napellusAconitum Napellus is one of the most toxic plants that is mostly found in mountainous regions of Asia and Europe. It is a beautiful plant with blue and purple color lobed leaves. It contains many alkaloid substances and one of them is aconitine. This substance can cause death when ingested. In general, a small amount of this plant can cause numbness, vomiting, and death in rare cases.

Castor Bean

castor-beanCastor bean plants are the fastest-growing shrubs that are mostly found in tropical and subtropical regions of the Earth. These plants are economically important due to the oil which is extracted from their seeds. The castor bean plant itself is not toxic and is safe for herbivores. However, the toxic substances are found in their seeds. They contain ricin, which is a poisonous substance. If the seeds of castor beans are eaten, they may cause vomiting, bloody diarrhea, increased heart rate, low blood pressure, and death in some cases. The toxic substance, ricin, is removed during the oil extraction process to make the oil safer.

Water Hemlock

water-hemlockWater hemlock plants belong to the Apiaceae family and are mostly found in North America. They have a beautiful appearance with small white-colored flowers. They also carry highly toxic substances, including cicutoxin. Most of the Cicutoxin is found in its roots which can cause seizures, respiratory system failure, and even death. Water hemlocks are very similar in appearance to edible plants, so control actions are taken in the US to contain them in certain areas.

Fun Facts

  • Leaves of the apple tree and its seeds contain ‘cyanide’; a very poisonous chemical.
  • Unripen potatoes are also poisonous; they may cause vomiting.
  • Some poisonous plants can cause very intense itching when touched, e.g. Poison Ivy.