Subtopic: Fundamentals of Biomolecules, enzyme kinetics
Question Statement:
function are CORRECT?
Which of the following combinations of plant hormones and their associated
Hormone
Function
P. Abscisic acid
Breaks seed dormancy
Q. Auxin
Induces cell division
R. Ethylene
Stimulates ripening of fruits
S. Gibberellin
Promotes seed dormancy
Options:
(A) P and R only
(B) P and S only
(C) Q and R only
(D) Q and S only
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2021 Q.41)**
**1. Governing Concept**:
- **Topic**: Plant Physiology & Phytohormone Functions
- Evaluating plant hormone functions:
- **P. Abscisic acid (ABA)**: **Promotes** and enforces seed dormancy (inhibits germination); does NOT break dormancy $\rightarrow$ **INCORRECT**.
- **Q. Auxin**: Promotes cell elongation, root initiation, and in combination with cytokinin **induces cell division** in plant tissue culture $\rightarrow$ **CORRECT**.
- **R. Ethylene**: Gaseous phytohormone that **stimulates fruit ripening** and senescence $\rightarrow$ **CORRECT**.
- **S. Gibberellin (GA)**: **Breaks** seed dormancy and promotes seed germination via $\alpha$-amylase induction; does NOT promote dormancy $\rightarrow$ **INCORRECT**.
- Therefore, the correct combinations are **Q and R only**.
**2. Option Analysis**:
- **Option (A) [P and R only] is INCORRECT**: Statement P is false (ABA promotes dormancy).
- **Option (B) [P and S only] is INCORRECT**: Both P and S ascribe inverted roles to ABA and GA.
- **Option (C) [Q and R only] is CORRECT**: Auxin induces cell division and Ethylene triggers fruit ripening.
- **Option (D) [Q and S only] is INCORRECT**: S is false (GA breaks dormancy).
**3. Final Answer**:
- **Correct Choice**: **C**
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