what are plant hormones class 10
Plant hormones (phytohormones) are chemical substances produced in very small amounts in different parts of a plant that control and coordinate growth, development and responses to the environment.
They move from where they are produced (like shoot tips, roots, seeds or young leaves) to other parts of the plant and influence processes such as cell division, cell elongation, seed germination, flowering, fruit ripening and leaf fall.
Simple definition for Class 10
- Plant hormones are chemical messengers in plants.
- They are made naturally inside the plant.
- They work even in very small quantities.
- They help plants grow, bend towards light, open and close stomata, shed leaves, ripen fruits, etc.
You can remember them as the plant’s “internal WhatsApp messages” that tell different parts what to do and when.
Major plant hormones in Class 10
For Class 10 (NCERT/CBSE type syllabus), you mainly need to know these five plant hormones:
- Auxins
- Gibberellins
- Cytokinins
- Abscisic acid (ABA)
- Ethylene (Ethene)
1. Auxins
- Made mostly in shoot tips and young leaves.
- Promote cell elongation and growth of stems.
- Help in bending of shoots towards light (phototropism) because auxin collects on the shaded side and causes those cells to grow longer.
- Used in agriculture to promote root formation in cuttings and to prevent premature fruit drop.
2. Gibberellins
- Promote stem elongation and growth in length.
- Help in seed germination by breaking seed dormancy.
- Used to increase the size of fruits like grapes and to induce flowering in some plants.
3. Cytokinins
- Promote cell division (cytokinesis).
- Delay ageing of leaves and keep them green for longer (used in storage of vegetables and cut flowers).
- Help in breaking seed dormancy and promote shoot formation in tissue culture.
4. Abscisic acid (ABA)
- Called a growth inhibitor or “stress hormone”.
- Promotes dormancy in seeds and buds and inhibits growth.
- Causes stomata to close during water stress, helping the plant conserve water.
- Helps in leaf fall and fruit drop.
5. Ethylene (Ethene)
- A gaseous plant hormone.
- Promotes fruit ripening and is used commercially to ripen fruits like bananas and mangoes.
- Helps in leaf fall and flower dropping and can break bud dormancy in some plants.
Quick exam-ready table (Class 10)
| Hormone | Type | Main functions (Class 10 level) |
|---|---|---|
| Auxin | Growth promoter | [5]Cell elongation, stem growth, root formation, bending towards light (phototropism). | [1][3][5]
| Gibberellin | Growth promoter | [5]Stem elongation, seed germination, bigger fruits, inducing flowering in some plants. | [1][3][5]
| Cytokinin | Growth promoter | [5]Cell division, breaking seed dormancy, delaying ageing of leaves. | [9][3][5]
| Ethylene | Growth promoter (mainly) | [5]Fruit ripening, leaf and flower drop, breaking bud dormancy. | [8][3][5]
| Abscisic acid (ABA) | Growth inhibitor | [3][5]Seed and bud dormancy, closing of stomata during stress, leaf fall. | [6][3][5]
How to write a perfect Class 10 answer
If the question is:
“What are plant hormones? Name four plant hormones and write one function of each.”
You can write:
- Plant hormones are chemical substances produced in plants that regulate growth, development and responses to stimuli, even when present in very small amounts.
- Four plant hormones and one function each:
- Auxin – causes cell elongation in stems and helps in bending of shoots towards light.
2. Gibberellin – promotes stem elongation and helps in seed germination.
3. Cytokinin – promotes cell division and delays ageing of leaves.
4. Abscisic acid – inhibits growth and causes seed dormancy and closing of stomata during stress.
This style matches what examiners expect for Class 10 biology right now and is aligned with current board-style explanations.
Meta description (for SEO):
Plant hormones for Class 10 explained in simple language: definition, types
(auxin, gibberellin, cytokinin, ethylene, abscisic acid) and key functions
with an exam-ready answer.
