It is a kind of plant organ that is used for anchoring and supporting the vining system. It can be a modified structure of leaves, leaflets, leaf tips, or leaf stipules. They may also be derived from modified stem branches like in grapes. They are thin, thread-like growths present on the stem or leaves of climbing plants. Based on growth tendril are of two types they are: stem tendril and leaf tendril. And their growth is mainly towards the support with which they can attach themself for the support and this phenomenon is known as thigmotropism.
Some of the common function of tendril are discussed below:
They are known to be modified portions of leaf, stem or petiole.
Their main function is to provide support to the plant as it climbs up a structure. By doing so they allow a plant to find a more suitable area to grow due to more light.
When stems are modified into tendril they help plants to climb.
The positions of tendril are different in different plants like in leaf, stem or even branches in few plants.
When stems are modified into threadlike leafless structure then they are known as stem tendril. Their major role is for climbing purposes, they don't necessarily contain a branch.
Axillary: E.g., Passiflora
Extra-Axillary: E.g., Luffa
Apical Bud: E.g., Grapevine
Floral Bud: E.g., Antigonon
It is a kind of curvature movement shown by a plant in response to a unilateral touch stimulus and can be observed in many climbers. In tendril climbers, the tendrils first show mutation, and as soon as their apices touch support, they move thigmotropic ally to turn around it.
Some of the common examples of tendril-producing plants are the grape, members of the squash or melon family (Cucurbitaceae), the sweet pea (Lathyrus odoratus), and the passion flowers (Passiflora species).
It is a kind of growth hormone which is generally synthesized at the shoot tip. It enhances the growth of cells so that plants can increase their length. As soon as the tendril comes in contact with any support system, auxin stimulates the cell to grow faster on the opposite side that’s why the tendril forms a coil around the support.
Naturally occurring auxins: Indole acetic acid, indole ethanol, indole acetaldehyde.
Synthetic auxins: Naphthalene acetic acid, indole butyric acid, 2, 4 - dichlorophenoxyacetic acid.
In Botany, tendrils are defined as the plant organ which is specialised for anchorage and supporting the vining stems. They can be defined as the modified leaves, leaf tips, leaflets or stipules. They can also be derived from modified stem branches like in grapes. Tendrils are distinct and are specialised structures which strongly possess a tendency to the leaf which then encircles any object it encounters. It is thus, slender and whip-like strand which is produced from the node of the stem which is a vine or plants that climb on objects or other plants. The anatomy of the tendrils may be like that of a leafstalk tissue or a stem tissue. Examples of plants having tendrils are grapes, melon family, squash family and peas. Tendrils are sensitive to contact and when it is bent towards the ground it actually bends towards the ground. When it encounters an object, it encircles the object and clings to it for a long time as long as the stimulation is persisted. Eventually, sclerenchyma which is a strong mechanical tissue develops in tendrils and supports the vining system which makes them strong enough to carry the weight of the plant.
Some of the tendrils produce terminal enlargements which come in contact with firm surfaces that flatten and secrete an adhesive which actually glues the tendril to the substrate. Based on the growth of the tendril, there are two types of them which are namely the stem tendril and leaf tendril. The difference between the stem tendril and the modified tendril is that the stem tendril is a modified stem but the leaf tendril is a modified leaflet, leaf or its part. Both their growth mainly supports the part to which they are attached to and gives support to them. This process is called thigmotropism.
1. Explain different modifications of parts of plants that form tendril?
Plants that undergo modification for tendril formation are:
In the case of pea plants, their terminal leaflets are modified to form a tendril.
In yellow Vetch, the whole leaf gets modified to form a tendril and their stipules enlarge themself for the photosynthesis process.
In case of the Pitcher plant, a specialised pitcher trap form tendril from one end.
So, in all such plants, their major function is to anchor themself to any support system to provide proper growth to plant in the direction of sunlight.
2. Name the plant in which stems are modified into tendril?
In pea plant i.e. Pisum sativum, their stem gets modified into tendril for the support system.
3. Who was the first to study tendril?
Charles Darwin was the very first to do a study of tendril and their movement.
4. What is the function of the tendril?
The tendrils have various functions and they are given as below:
They are modified parts of a leaf, petiole or stem.
The tendrils have the main function of providing support to the plant when it has to climb on an object. This allows the plant to grow at a suitable place getting the required amount of sunlight.
When the stems are modified into tendril i.e. the stem tendrils help the plants to climb.
Positions of tendril differ in different plants like the parts of leaf, stem or even branches in some plants.
5. What is thigmotropism?
Thigmotropism can be defined as the curve movement made by the plant in response to a touch stimulus which is observed in many climber plants. In tendrils, when they come in contact with an object then they respond to the stimulus and start circling around it. This gives it a whip-like or thread-like structure. Both the stem and leaf tendrils’ growth mainly supports the part to which they are attached to and gives support to them. This process is called thigmotropism.
6. What are the effects of Auxin in plants?
Auxin is a plant hormones and it has 3 effects which are as follows:
Elongation of shoot stimulation: The length of the plant depends on the hormones called gibberellins which are regulated by auxins.
Seedling orientation: Seedlings tend to grow towards sunlight and the presence of auxins influence all the cells present in the plants. The auxin hormone is affected by gravity which results in its accumulation on the bottom. Thus, the cells grow where there is a high concentration of this hormone.
Root branching: Roots can be obtained by applying auxin on the cuts.
Fruit development: Auxins help in the growth of flower and also the maturation of ovary and in fruit development.
7. What is the role of auxin in tendril growth? Explain.
Auxin is a plant hormone which is synthesised at the shoot tip and it helps in cell growth thus, in plant growth. When a tendril encounters a substance or support then the auxin stimulates the growth of cells in a fast pace which is in the opposite direction. This is why the tendril takes the shape of a coil. Auxin helps in the growth of cells which helps the plant to increase their length. Thus, auxins play a major role in the growth of tendrils and also in the growth of plants.
8. Can I get free notes on tendrils on Vedantu?
Yes, Vedantu provides all the necessary study materials on tendrils and other topics of botany as well. Students can download the free notes as a PDF file from any of the Vedantu platforms (app or website). All you have to do is sign up or log in to Vedantu and get access to the notes, revision notes and even give mock tests. Furthermore, students can clear their doubts from the Vedantu tutors which are free of cost as well.