Question:
The compound discovered as natural trigger for the metabolic explosion that raises the temperature of thermogenic inflorescence of Arum lillie is: [Question ID = 718][Question Description = 218_34_PLB_AUG22_Q118]
The compound discovered as natural trigger for the metabolic explosion that raises the temperature of thermogenic inflorescence of Arum lillie is: [Question ID = 718][Question Description = 218_34_PLB_AUG22_Q118]
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Alternative Oxidase (AOX) = Heat production. Salicylic acid = Trigger for AOX in voodoo lilies.
Updated On: Aug 7, 2026
- Abscisic acid [Option ID = 2869]
- Salicylic acid [Option ID = 2870]
- Brassino steroids [Option ID = 2871]
- Ethylene [Option ID = 2872]
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The Correct Option is B
Solution and Explanation
Step 1: Understanding the Concept:
Thermogenesis is the production of heat in certain plants, specifically in the inflorescences of the Araceae family (like Arum lilies). This heat production helps in the volatilization of scent compounds to attract pollinators. The discovery of the molecular trigger for this phenomenon is a landmark in plant signaling.
Step 2: Detailed Explanation:
1. The Phenomenon: In Arum lilies, the spadix temperature can rise significantly (often \(10-15^{\circ}C\) above ambient air) for a short period.
2. The Discovery: Researchers (Raskin et al., 1987) identified that Salicylic Acid (SA) levels increase dramatically (up to 100-fold) just before the onset of thermogenesis.
3. Mechanism: Salicylic acid acts as a signal that induces the expression and activity of the Alternative Oxidase (AOX) enzyme in the mitochondria. The AOX pathway bypasses the energy-conserving steps of the normal respiratory chain (where ATP is made), instead releasing the energy of electron transport directly as heat. This "metabolic explosion" is the biochemical basis for the temperature rise.
4. While SA is better known for its role in systemic acquired resistance (SAR) against pathogens, its discovery as a "calorigen" (heat-producing factor) in thermogenic plants was one of its first recognized hormonal functions.
Step 3: Final Answer:
Salicylic acid is the compound that triggers thermogenesis in Arum lilies.
Thermogenesis is the production of heat in certain plants, specifically in the inflorescences of the Araceae family (like Arum lilies). This heat production helps in the volatilization of scent compounds to attract pollinators. The discovery of the molecular trigger for this phenomenon is a landmark in plant signaling.
Step 2: Detailed Explanation:
1. The Phenomenon: In Arum lilies, the spadix temperature can rise significantly (often \(10-15^{\circ}C\) above ambient air) for a short period.
2. The Discovery: Researchers (Raskin et al., 1987) identified that Salicylic Acid (SA) levels increase dramatically (up to 100-fold) just before the onset of thermogenesis.
3. Mechanism: Salicylic acid acts as a signal that induces the expression and activity of the Alternative Oxidase (AOX) enzyme in the mitochondria. The AOX pathway bypasses the energy-conserving steps of the normal respiratory chain (where ATP is made), instead releasing the energy of electron transport directly as heat. This "metabolic explosion" is the biochemical basis for the temperature rise.
4. While SA is better known for its role in systemic acquired resistance (SAR) against pathogens, its discovery as a "calorigen" (heat-producing factor) in thermogenic plants was one of its first recognized hormonal functions.
Step 3: Final Answer:
Salicylic acid is the compound that triggers thermogenesis in Arum lilies.
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