Question

Deficiency symptoms of nitrogen and potassium are visible first in

• A. senescent leaves
• B. young leaves
• C. roots
• D. buds.

Answer 1

The Correct Option is A

The question is about identifying the first visible symptoms of deficiencies in nitrogen and potassium within a plant. Understanding how different nutrient deficiencies affect plants is crucial for effective plant management, especially in agriculture and botany.

To solve this, we start by considering the movement and role of these nutrients:

1. Nitrogen and Potassium Mobility: Nitrogen and potassium are both mobile nutrients within a plant. When a plant experiences a deficiency in mobile nutrients, it tends to move these nutrients from older to newer leaves to support growth.
2. Deficiency Symptoms: Since these nutrients can be relocated from older tissues, symptoms of their deficiency first appear in the older, or senescent, leaves as the plant moves available resources to newer tissues.
3. Explanation of Symptoms in Senescent Leaves: Senescent leaves, naturally nearing the end of their lifecycle, show the first signs of deficiencies like yellowing (chlorosis) due to nitrogen shortage or burning and curling because of potassium deficiency. Young leaves remain relatively unaffected initially, as they receive nutrients relocated from older leaves.

After evaluating the movement and function of these nutrients, we conclude that the deficiency symptoms of nitrogen and potassium are first visible in the "senescent leaves." This understanding is critical for diagnosing plant health issues and implementing timely nutrient management strategies.

Thus, the correct answer is senescent leaves.