Question

Which of the following plant hormones controls fruit ripening?
1. Ethylene
2. Zeatin
3. Auxins
4. Gibberellic acid

Answer 1

Correct Answer - Option 1 : Ethylene

The correct answer is Ethylene.

• Ethylene is known as the natural fruit-ripening hormone.
• Ripening is the process by which fruits attain their desirable flavour, quality, colour, palatable nature.
  • Ripening is associated with a change in composition i.e. conversion of starch to sugar.
  • During ripening enzymatic breakdown and hydrolysis (reaction with water) of polysaccharides like starch takes place.
  • Starch breaks down into smaller molecules like fructose, glucose, sucrose etc.

 

• Zeatin promotes the growth of lateral buds and when sprayed on meristems stimulates cell division to produce bushier plants.
• Auxin regulates growth, particularly by stimulating cell elongation in stems.
• Gibberellic acid (GA) is a plant hormone that stimulates plant growth and development.

• For the artificially ripening of the fruits, Calcium Carbide (CaC2) is used.
  • In artificial ripening, unlike natural ripening, a ripening agent is used to promote the ripening of fruits and to induce a colour change.
  • Unsaturated hydrocarbons such as acetylene, ethylene etc. can promote ripening and induce colour changes.
  • When Calcium Carbide reacts with water, it produces acetylene gas and quickens the ripening process.
  • Reaction- CaC2 + 2H2O → C2H2 + Ca (OH)2