Untitled Quiz

Deficiency Symptoms and Nutrient Functions

• Nitrogen (N) Deficiency:

  • Dark green leaves and stems, stunted growth.
  • Purplish discoloration in older leaves, delayed maturity.
  • In small grains, predisposes to root rot; in alfalfa, upward tilting of leaflets; in potatoes, upward curling and brown specks in tubers; in corn, purple leaves in young plants.

• Potassium (K) Functions:

  • Activates enzymes, aids in photosynthesis, protein formation, and sugar transport.
  • Initial reduced growth rate leads to chlorosis and necrosis in older leaves.
  • Symptoms include mottled leaves, reduced stalk strength, and impaired disease resistance.
  • Specific effects seen in small grains (excessive tilling), alfalfa (white leaf spots), and root crops (small tubers).

• Chloride (Cl) Functions:

  • Essential for leaf turgor and photosynthesis.
  • Symptoms include chlorotic spotting, wilting margins, and branching root systems in cereals.

• Magnesium (Mg) Functions:

  • Central component of chlorophyll and co-factor in ATP production.
  • Deficiency shows as interveinal chlorosis, yellowing leaf margins, and mottling in grains and alfalfa curling.

• Molybdenum (Mo) Functions:

  • Important for enzyme activity and nitrogen fixation in legumes.
  • Symptoms resemble nitrogen deficiency with stunted growth, pale leaves, and scorching.

Immobile Nutrients

• Sulfur (S) Functions:

  • Constituent of amino acids and proteins.
  • Symptoms include yellow younger leaves and spindly plants with thin stems.

• Boron (B) Functions:

  • Crucial for cell wall formation and reproductive tissue development.
  • Deficiency leads to chlorotic young leaves, necrosis, brittle leaves, and poor flowering and seed viability.

• Iron (Fe) Functions:

  • Vital for respiratory and photosynthetic processes.
  • Interveinal chlorosis in young leaves signifies deficiency, advancing to pale, slow-growing plants.

• Zinc (Zn) Functions:

  • Involved in growth hormone production and stem elongation.
  • Deficiency symptoms include middle leaf chlorosis, stunting, poor flowering, and distinctive leaf colorations.

• Calcium (Ca) Functions:

  • Key component of cell walls and structure regulation.

Mineral Nutrition Overview

• Mineral nutrients are essential elements absorbed mostly as inorganic ions from the soil.
• Plants absorb minerals for biological functions, aided by mycorrhizal fungi and nitrogen-fixing bacteria.

Essential Mineral Elements

• Essential elements are classified as macronutrients (needed in larger amounts: nitrogen, phosphorus, potassium) and micronutrients (needed in smaller amounts: iron, manganese, zinc).
• Elements must fulfill specific criteria to be deemed essential.

Nutritional Study Techniques

• Historical plant growth experiments highlighted early nutrient acquisition techniques.
• Hydroponics: Cultivating plants in nutrient solutions; utilizes vigorous oxygen bubbling and various media.
• Aeroponics: Roots are suspended in air, continually sprayed with nutrient solutions.

Other Deficiency Symptoms

• Copper (Cu) Functions:

  • Promotes chlorophyll production and respiration. Symptoms include chlorosis in young leaves and poor grain yield.

• Manganese (Mn) Functions:

  • Critical for chloroplast function; deficiencies lead to interveinal chlorosis and visible specks or mottling in crops.

• Nickel (Ni) Functions:

  • Essential for seed germination and nitrogen metabolism; deficiency results in chlorosis, tissue necrosis, and decreased yields.

Root-Microbe Interactions

• Rhizosphere: Soil region influenced by root activity supporting microorganism associations.
• Bacterial Contributions: Facilitate nitrogen fixation and root growth improvements.
• Mycorrhizal Fungi: Amplify nutrient absorption capabilities and extend root reach.

Types of Mycorrhizae

• Ectotrophic Mycorrhizae: Form a protective sheath and enhance tree nutrient uptake.
• Vesicular Arbuscular Mycorrhizae (VAM): Extend nutrient exchange area without invading root cell protoplasts.

Importance of Mycorrhizae

• Enhance root nutrient absorption, extend beyond nutrient-depleted soil, and increase cytoplasmic volume for efficient nutrient exchange.