The Question is from neet-botany morphology-of-flowering-polants seed, and it was created by the author D VINOD

Question

A dormant seed of a desert plant exhibits an extremely low metabolic rate. Which of the following biochemical changes contributes MOST significantly to this state?

D VINOD · Accepted Answer

## CORE INFORMATION
✓ **Answer**: B
## CONCEPT FRAMEWORK
 **Primary Concept**: Plant dormancy and its hormonal regulation
 **Related Topics**: Abscisic acid (ABA) function, seed germination, metabolic rate, plant stress responses
 **Prerequisites**: Understanding of plant hormones and their roles in growth and development.
## SOLUTION PATHWAY
**Given Information**:
  A dormant desert plant seed has a very low metabolic rate.
  We need to identify the biochemical change most responsible for this low metabolic rate.
**Method & Steps**:
 1. Analyze the role of each hormone in seed dormancy and metabolic rate.
  Reasoning:  Dormancy is a survival mechanism, particularly in harsh environments like deserts.  Hormones play a crucial role in initiating and maintaining this state.
 2. Evaluate each option's impact on metabolic rate.
  Working:
  * **Option A (Increased gibberellin and rapid cell division):** Gibberellins promote growth and germination, which are associated with *increased* metabolic activity, opposite to the given condition.
  * **Option B (High ABA levels and dehydration):** Abscisic acid (ABA) is a key hormone in seed dormancy. It inhibits germination and reduces metabolic processes. Dehydration further reduces metabolic activity.
  * **Option C (Elevated ethylene and fruit ripening):** Ethylene is associated with fruit ripening and senescence, not directly related to seed dormancy in this context.
  * **Option D (Increased cytokinin and enhanced protein synthesis):** Cytokinins promote cell division and growth, leading to *higher* metabolic rates, opposing the given condition.
 3. Identify the option that best explains the low metabolic rate.
  Result: Option B, high ABA levels and dehydration, is the most significant contributor to the low metabolic rate in a dormant desert plant seed.  ABA inhibits germination and metabolic processes, and dehydration further reduces metabolic activity.
  Verification: The characteristics of ABA and dehydration align perfectly with the observed low metabolic rate in a dormant seed. 
 ## OPTION ANALYSIS
[A] :x: Increased gibberellin biosynthesis and rapid cell division would increase metabolic rate, the opposite of what is observed in a dormant seed.
[B] ✓: High abscisic acid (ABA) levels and dehydration of cellular components are key factors in maintaining seed dormancy and reducing metabolic rate. ABA is a stress hormone that inhibits growth and metabolism, and dehydration further slows down metabolic processes.
[C] :x: Elevated ethylene production and fruit ripening processes are unrelated to seed dormancy in desert plants.
[D] :x: Increased cytokinin concentration and enhanced protein synthesis would increase metabolic activity, contradicting the observation of a low metabolic rate.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing the roles of different plant hormones:  Understanding the specific functions of ABA, gibberellins, cytokinins, and ethylene is crucial.
  2.Overlooking the role of environmental factors:  Dehydration is a significant factor in reducing metabolic rate in desert plants.
 **Quick Tips**:
  1.Remember ABA as the 'dormancy hormone'.
  2.Associate high ABA levels with low metabolic activity and dehydration with reduced metabolic activity in seeds.

D VINOD · Answer

Increased gibberellin biosynthesis and rapid cell division

D VINOD · Answer

The correct Option is "High abscisic acid (ABA) levels and dehydration of cellular components"

D VINOD · Answer

Elevated ethylene production and fruit ripening processes

D VINOD · Answer

Increased cytokinin concentration and enhanced protein synthesis

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