Question

Name the hormone which is responsible for apical dominance.

Hint:

Cytokinins play a crucial role in regulating plant growth and development, particularly in shoot growth and delaying aging in plants.

Answer 1

Step 1: Understanding Apical Dominance.
Apical dominance is the phenomenon where the growth of lateral buds is inhibited by the presence of the apical bud. This is controlled by a plant hormone called Auxin.
Step 2: Conclusion.
Auxin is the hormone responsible for apical dominance, and it prevents the growth of lateral buds, ensuring the plant grows taller.
ii. A farmer wants to remove broad-leaved weeds from the jowar plantation in his field. Suggest any plant hormone to remove such weeds.
Solution:
Step 1: Understanding the Role of Plant Hormones in Weed Control.
To remove broad-leaved weeds, the farmer can use 2,4-D (a synthetic auxin). It is selective in its action, promoting uncontrolled growth in dicot weeds, which leads to their death.
Step 2: Conclusion.
2,4-D is an effective herbicide that targets broad-leaved weeds without harming monocot crops like jowar.
iii. Mention any two applications of cytokinin.
Solution:
Step 1: Understanding Cytokinins.
Cytokinins are plant hormones that promote cell division and growth. They have several applications in agriculture and plant tissue culture.
Step 2: Applications of Cytokinins.
1. Promotion of Shoot Growth: Cytokinins are used in tissue culture to promote the growth of shoots and buds from plant explants.
2. Delay of Senescence: Cytokinins can delay leaf senescence, extending the shelf life of cut flowers and fruits by preventing premature aging.
Step 3: Conclusion.
Cytokinins are widely used in plant growth and agricultural practices, particularly in tissue culture and extending the shelf life of plants.