Question

When the plants are grown in magnesium deficient but urea rich soil; the symptoms expressed are:

• A. Yellowish leaves
• B. Colourless petiole
• C. Dark green leaves
• D. Shoot apex die

Answer 1

The Correct Option is A

To address the question regarding the symptoms expressed by plants grown in magnesium-deficient but urea-rich soil, we need to understand the role of magnesium and how its deficiency manifests in plants.

Magnesium's Role in Plants:

• Magnesium is a key component of chlorophyll, the green pigment essential for photosynthesis in plants.
• It is involved in enzyme activation, nucleic acid synthesis, and maintaining the structural integrity of proteins.

Symptoms of Magnesium Deficiency:

• One of the primary symptoms is chlorosis, which is the yellowing of leaves, especially older leaves.
• The yellowing occurs because chlorophyll production is compromised, affecting photosynthesis.
• The veins of the leaves often remain green while the areas between them turn yellow, a phenomenon known as interveinal chlorosis.

Given these details, among the provided options, the symptom that aligns with magnesium deficiency in a context where the soil is still urea-rich (high nitrogen but low magnesium) is:

• Yellowish leaves: This is correct because magnesium deficiency leads to reduced chlorophyll, resulting in yellowing.
• Colourless petiole: This is not specifically tied to magnesium deficiency.
• Dark green leaves: This is opposite to what occurs since magnesium deficiency reduces the green pigment.
• Shoot apex die: This is a symptom more commonly linked to severe nitrogen deficiency or other factors.

Therefore, the correct answer is Yellowish leaves.