Plant Nutrition ÔÇô Mineral Requirements

Objective

Describe the symptoms in a plant with nitrate ion deficiency and magnesium ion deficiency.

Nitrate Ion Deficiency

Nitrate (NO₃^-) is an essential nutrient for plant growth, primarily involved in the synthesis of amino acids, proteins, and nucleic acids. Deficiency in nitrate leads to several characteristic symptoms:

• General Yellowing (Chlorosis): Older leaves are typically affected first, exhibiting a general yellowing of the foliage.
• Leaf Colour Progression: The yellowing starts with the older, lower leaves and progresses upwards.
• Stunted Growth: Overall plant growth is reduced.
• Reduced Yield: Lower fruit or grain production is observed.
• Weak Stems: Stems may appear weak and spindly.

Magnesium Ion Deficiency

Magnesium (Mg²⁺) is a central component of the chlorophyll molecule and is crucial for photosynthesis. Deficiency in magnesium results in the following symptoms:

• Interveinal Chlorosis: Yellowing occurs between the veins of the leaves, while the veins themselves remain green. This is a key identifying symptom.
• Leaf Margin Necrosis: The edges of the leaves may turn yellow and then brown or die (necrosis).
• Leaf Curling: Leaves may curl upwards or downwards.
• Reduced Photosynthesis: The plant's ability to carry out photosynthesis is impaired.
• Weak Stems: Similar to nitrate deficiency, stems can become weak.

Summary Table

Suggested diagram: A diagram showing a plant with interveinal chlorosis (magnesium deficiency) and a plant with general chlorosis (nitrate deficiency) would be helpful for visual understanding.