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प्रश्न
Name various plant hormones. Also give their physiological effects on plant growth and development.
उत्तर
There are five major types of plant hormones: auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
- Auxins - When the growing parts of a phototropic plant detect sunlight, auxins (synthesized at the shoot tips) help the cells grow longer. When light falls on one side of the plant, the auxins generally diffuse towards the shaded side of the shoot. They also helps in root formation, apical dominance, inhibition of abscission and fruit growth.
- Gibberellins - They are produced in the roots of a plant. They promote stem elongation by promoting cell division in the inter-nodal region.
- Cytokinins - They promotes cell division. Therefore, they are present in greater concentration in those areas of the plants where rapid cell division occurs. For example, the tip of the shoot.
- Abscisic acid - It promotes seed dormancy by inhibiting cell growth. It is involved in the opening and closing of stomata. It is also responsible for the shedding of leaves.
- Ethylene - It regulates fruit ripening. It is produced during the ripening of fruits.
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संबंधित प्रश्न
Stems are
Name the following:
Growth-retarding hormone in plants.
List five plant growth hormones and briefly describe their roles.
Write the name of______
- First hormone discovered in plants.
- Biological name of fungus from which Gibberellins were first isolated.
- The name given to the first cytokinin by Skoog and Miller.
Which hormone induces parthenocarpy in tomatoes?
The active ingredient of Agent Orange is an egual mixture of two phenoxy herbicides ____________.
Match the following lists and select the correct option.
| List I | List II | ||
| i. | 2,4-D | a. | Promotes senescence and ripening of fruits |
| ii. | ABA | b. | DelaysJeaf senescence |
| iii. | Gibberellins | c. | Increases the length of the sugarcane stem |
| iv. | Ethylene | d. | Kills dicotyledonous weeds without affecting mature monocotyledonous plants |
| e. | Stimulates the closure of stomata |
First cytokinin was discovered by Skoog and Miller while working on tissue culture of ____________ plant.
Give one example of Parthenocarpy.
The response by parts of the plant towards stimulus is called as ______.
