The correct Answer is A-4, B-3, C-1, D-2
Explanation
Plant hormones, also known as phytohormones, are chemical substances that regulate plant growth and development. They are produced in small quantities within the plant and control various physiological processes such as cell division, elongation, differentiation, flowering, fruiting, and senescence. Key plant hormones include auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
Statement-wise Analysis
- Auxin (A):
- Correct Match: 4. Promotes cell elongation and bending towards light.
- Justification: Auxins are primarily responsible for cell elongation, particularly in shoots. They play a crucial role in phototropism (bending towards light) and gravitropism (response to gravity) by influencing cell growth on different sides of the stem or root.
- Gibberellins (B):
- Correct Match: 3. Promotes growth of stem.
- Justification: Gibberellins are known for promoting stem elongation, particularly in dwarf varieties, and also play a role in seed germination and flowering.
- Cytokinins (C):
- Correct Match: 1. Promotes rapid cell division.
- Justification: Cytokinins are essential for cell division (cytokinesis) and differentiation. They are found in areas of active cell division, such as root tips, developing shoots, and young fruits.
- Abscisic acid (D):
- Correct Match: 2. Inhibits growth and causes wilting.
- Justification: Abscisic acid (ABA) is a growth-inhibiting hormone. It promotes dormancy in seeds and buds, and its primary role in stress response includes causing stomatal closure, which can lead to wilting under water stress conditions.
Key Takeaway
Plant hormones regulate specific physiological processes; auxins promote cell elongation and phototropism, gibberellins promote stem growth, cytokinins stimulate cell division, and abscisic acid inhibits growth and induces stress responses like wilting.