Question

Identify the incorrect statement/s.
1. Kinetin is a derivative of Adenine which is a pyrimidine.
2. The technique of decapitation is widely used in tea plantations.
3. Ethylene is a gaseous plant hormone.
4. Use of GA₃ hastens the malting process in brewing industry.
5. ABA is a growth promoter.

• A. 1, 2, 3, 4
• B. Only 3
• C. 2, 3, 4
• D. 1 and 5

Answer 1

The Correct Option is D

Let's evaluate each statement about plant hormones and their applications:

1. "Kinetin is a derivative of Adenine which is a pyrimidine."
   • Kinetin is a synthetic cytokinin, a class of plant hormones that promote cell division. Its chemical structure is derived from Adenine.
   • Adenine is a nitrogenous base belonging to the Purine group (double-ring structure), not the Pyrimidine group (single-ring structure).
   • Therefore, the statement that Adenine is a pyrimidine is incorrect, making the entire statement incorrect.
2. "The technique of decapitation is widely used in tea plantations."
   • Decapitation refers to the removal of the apical bud (shoot tip). 
   • The apical bud produces auxin, which causes apical dominance, suppressing the growth of lateral buds.
   • Removing the apical bud removes the auxin source, allowing lateral buds to grow, leading to a bushier plant.
   • This practice is common in tea plantations and hedge-making to encourage dense growth.
   • This statement is correct.
3. "Ethylene is a gaseous plant hormone."
   • Ethylene (C₂H₄) is unique among the major plant hormones as it is a gas at physiological temperatures.
   • It plays roles in fruit ripening, senescence, abscission, and stress responses.
   • This statement is correct.
4. "Use of GA₃ hastens the malting process in brewing industry."
   • GA₃ (Gibberellic Acid) promotes seed germination by stimulating the production of hydrolytic enzymes like α-amylase in the aleurone layer of cereal grains (like barley).
   • Malting involves the controlled germination of barley, where these enzymes break down stored starch into fermentable sugars.
   • Applying GA₃ speeds up enzyme synthesis and thus hastens the malting process.
   • This statement is correct.
5. "ABA is a growth promoter."
   • ABA (Abscisic Acid) generally acts as a plant growth inhibitor.
   • It promotes dormancy in seeds and buds, induces stomatal closure during water stress, and plays a role in senescence and abscission. It counteracts the growth-promoting effects of auxins and gibberellins in many situations.
   • This statement is incorrect.

The incorrect statements are 1 and 5.

Comparing this to the options:

• 1, 2, 3, 4
• Only 3
• 2, 3, 4
• 1 and 5

The correct option is 1 and 5.

Answer 2

Let's evaluate each statement:

Kinetin is a derivative of Adenine which is a pyrimidine:

• This is incorrect. Kinetin is a type of cytokinin, which is a derivative of adenine, but adenine is a purine, not a pyrimidine.

The technique of decapitation is widely used in tea plantations:

• This is correct. Decapitation (removal of the growing tip) helps in promoting lateral growth and increases the yield of tea leaves.

Ethylene is a gaseous plant hormone:

• This is correct. Ethylene is indeed a gaseous plant hormone that plays a key role in ripening, senescence, and stress responses in plants.

Use of GA3 hastens the malting process in the brewing industry:

• This is correct. GA3 (Gibberellic acid) is used to promote the germination of barley seeds during malting, speeding up the process.

ABA is a growth promoter:

• This is incorrect. Abscisic acid (ABA) is a plant hormone that inhibits growth and promotes dormancy, especially in seeds, and it is known as a growth inhibitor.

The incorrect statements are 1 and 5.

The correct answer is (D) : 1 and 5.