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Which of the following is a negative senescence regulator?

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  1. Ethylene
  2. Abscisic acid
  3. Jasmonic acid
  4. Cytokinins

Answer (Detailed Solution Below)

Option 4 : Cytokinins
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Detailed Solution

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The correct answer is Cytokinins

Concept:

  • Senescence is the process of aging in plants, leading to the death of cells, tissues, or the entire plant. This process is regulated by various plant hormones.
  • Negative senescence regulators are substances that delay or inhibit the aging process in plants.
  • Cytokinins are a class of plant hormones that play a crucial role in promoting cell division and growth, and they are known to delay senescence.

Explanation:

  • Ethylene: This plant hormone is known to promote senescence and ripening in plants. It accelerates the aging process and is not a negative senescence regulator.
  • Abscisic acid: Often associated with stress responses in plants, abscisic acid promotes senescence by facilitating leaf drop and dormancy. It does not inhibit the aging process.
  • Jasmonic acid: This hormone is involved in plant stress responses and defense mechanisms. It promotes senescence and is not a negative senescence regulator.
  • Cytokinins: These hormones are known to delay the aging process by promoting cell division and growth. They inhibit senescence by maintaining chlorophyll and protein levels in plant tissues.
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