What is Tropism?

Tropism Meaning- Tropism is an organism's natural tendency to transform or shift in response to a stimulus. Innate responses, unlike acquired abilities, are genetically programmed. Tropism causes organisms to spontaneously gravitate toward a stimulus. Individual tropisms are also called after the stimulus that triggers the movement, which can be any signal from the setting. The animal would shift toward stimulation in an optimistic tropism. The animal would shift away from the tropism in a negative tropism. Since certain stimuli are always beneficial or always harmful to an organism, they become genetically ingrained. Taxis are movements that are triggered by tropism.


What is Tropism in Viruses?

Tropism meaning in viruses- Viruses and other pathogens may also cause what is known as "host tropism," "tissue tropism," or "cell tropism," which refers to how various viruses/pathogens have evolved to preferentially target particular host organisms, tissues, or cell types inside those species. Tropisms are named for the stimulus they are reacting to (for example, a phototropism is a reaction to sunlight) and may be positive (towards the stimulus) or negative (against the stimulus) (away from the stimulus).


What are Tropism Types?

Different Types of Tropism-

Phototropism: Many photosynthetic animals use sunlight to grow their food. As a result, many species have evolved to use sunlight as a stimulus. Many of these species are attempting to reach the sun. Organisms shift into the light due to positive phototropism. Positive phototaxis is seen in many algae, plankton, and small invertebrates. This takes them to the same spot in the ocean, which has the most light by far. Even non-photosynthetic species have established this tropism, which draws them into the same water column as their prey. Other species can have a negative reaction to light and attempt to avoid it. When you uncover a beetle from its hiding spot, think of it as a beetle. Since darkness is generally associated with defence, the beetle will seek it out. This tropism has the same stimulus as plant tropism, but it works in the opposite direction.


Heliotropism: In land plants, a related phenomenon exists. Because of their roots, terrestrial plants are limited in their movement. Plants, on the other hand, orient their leaves toward the sun in order to collect as much sunlight as possible. This tropism is similar to phototropism, except the organism's location is fixed. Instead, the plant changes the turgor pressure, or water pressure, in individual cells to transform its leaves. Many crops, including sunflowers, corn, and even garden flowers, exhibit this trait. Following the sun's path means that the plants get the most amount of light possible.


Chemotropism: Chemotropism, or the inclination to transform or shift towards or away from a particular chemical element, is a common tropism in the animal kingdom. Chemo Tropisms are used by certain single-celled species for a variety of purposes. For example, one chemical may indicate the presence of a partner, while another may indicate the presence of a dangerous or unpleasant environment. These simple organisms would simply shift towards or away from stimuli in the direction that their forefathers found to be most evolutionary rewarding. Certain chemicals also attract animals in higher species, but they may not always travel towards it. To put it another way, although they have tropism, they do not always show taxis. Sharks, for example, have a positive chemotropism for blood, which means they gravitate toward it. A shark, on the other hand, would often examine or test a meal before devouring it, demonstrating that other processes can override a tropism.


Other Tropisms: Since species can detect a wide range of stimuli, several other tropisms occur in nature. Other species can detect stimuli we may not even be aware are present, whereas our senses are limited to a narrow visual, auditory, and tactile range. Scientists have identified a variety of stimuli that tend to be linked to a particular tropism. Here are a few examples:

  1. Thermotropism: A tropism in which species gravitate toward a certain temperature.

  2. Thigmotropism: When roots come into contact with a hard surface, such as rock, they sometimes transform. This tropism is triggered by the stimulus of touch

  3. Magnetotropism: Many animals may be attracted to certain poles by magnetic fields that serve as a source of direction.


Types of Tropism in Plants

  • Aerotropism is the movement of plants toward or away from an oxygen source.

  • Chemotropism is the movement or development of an organism in response to a chemical stimulus.

  • Movement or development in response to an electric field is known as electrotropism.

  • Exotropism is the continuation of development "outward," i.e. in the same direction as before.

  • Geotropism (also known as gravitropism) is the movement or development of an object in response to gravity.

    • Negative geotropism is also known as apogeotropism.

  • Diurnal or seasonal movement of plant parts in response to the position of the sun is known as heliotropism (e.g. the sunflower).

    • Negative heliotropism, apheliotropism.

  • Hydrotropism is the movement or growth of plants in response to water; the root cap detects variations in soil water moisture and signals cellular changes that cause the root to curve towards the higher moisture region. [two]

    • Positive hydrotropism: prohydrotropism

  • Hygrotropism is the movement or growth of plants as a result of moisture or humidity.

  • Magnetotropism is the movement or expansion of an object in response to magnetic fields.

  • Orthotropism refers to movement or development along the same axis as the stimulus.

  • Plagiotropism refers to movement or development that occurs at an angle to a stimulus line such as gravity or light.

  • Phototropism is the movement or development of an organism in response to light or light colours.

    • Negative phototropism: aphototropism

    • Skototropism, or negative phototropism in vines, is a form of negative phototropism.

  • Selenotropism is the movement of plant parts in response to the moon's direction.

  • Thermotropism is the movement or development of an organism in response to changes in temperature.

  • Thigmotropism is the movement or expansion of a body in response to touch or contact.

Types of Tropism in Virus

  • Wide host range: amphotropism (e.g. infects many species or cell types)

  • Small host selection: ecotropism (e.g. infects only one species or cell type)

  • HIV tropism refers to how a particular strain of HIV enters cells.

  • A virus that preferentially infects the nervous system of the host is known as neurotropism.

FAQs (Frequently Asked Questions)

Q1. What is Meant by Tropism? Define Tropism.

Ans. Tropism is a biological process in which a biological organism, normally a plant, grows or turns in response to an environmental stimulus. This response is influenced by the stimulus's direction in tropisms (as opposed to nastic movements which are non-directional responses). Viruses and other pathogens may also cause what is known as "host tropism," "tissue tropism," or "cell tropism," which refers to how various viruses/pathogens have evolved to preferentially target particular host organisms, tissues, or cell types inside those species.

Q2. Name any Two Types of Tropism.

Ans. Phototropism (response to light), geotropism (response to gravity), chemotropism (response to specific substances), hydrotropism (response to water), thigmotropism (response to mechanical stimulation), traumatotropism (response to wound lesion), and galvanotropism (response to electricity) are all examples of tropism.