Plant Nutrients and Photosynthesis

Plant Nutrients

Nutrients Required for Plant Growth

• Non-Mineral Nutrients:
  • Carbon (C), Hydrogen (H), Oxygen (O). Generally available through air and water.
• Primary Macronutrients:
  • Nitrogen (N), Phosphorus (P), Potassium (K). Available through soil, but usually not through fertilizers.
• Secondary Macronutrients:
  • Calcium (Ca), Magnesium (Mg), Sulfur (S).
• Micronutrients:
  • Nickel (Ni), Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B), Molybdenum (Mo), Chlorine (Cl).

Nutrient Deficiency Effects

• Nitrogen (N): Light green upper leaves, yellow leaves, yellow and shriveled.
• Phosphorus (P): Leaves are darker than usual.
• Potassium (K): Yellowish at edges and tips with dead spots and yellow patches.
• Magnesium (Mg): Lower leaves turn yellow from outside.
• Iron (Fe): Yellow leaves or leaves with green veins.
• Calcium (Ca): Stunted and misshapen new leaves; white deposits and stunted growth.
• Manganese (Mn): Yellow spots and elongated holes.
• Sulphur (S): Light or pale green leaves.
• Zinc (Zn): Pale, narrow leaves and short darker veins.

Role of Nitrogen

• Essential part of chlorophyll.
• Component of nucleic acids (DNA).
• Component of ATP (energy-transfer compound).
• Essential part of living cells, proteins, and enzymes.
• Stimulates root growth and crop development.

Nitrogen Metabolism

• Inorganic (nitrate NO3, ammonium NH4) and organic N is taken up by plants.
• Nitrate transporters (NRTs) function in nitrate absorption and transportation.
• Nitrate > Nitrite > Ammonia > Glutamate – provides N to other amino acids.
• Nutrient changes alter levels of gene transcription and protein abundance.
• GS/GOGAT pathway.

Plant Responses to Nutrient Changes

• Plants have evolved to cope with different environments.
• Differences in genetics + Differences in gene transcription levels (transcriptome) + Differences in protein activity (proteome) = Differences in phenotype.

Summary Points

• Plants require nutrients from the soil for growth and development.
• Amount of nutrients directly relates to yield.
• Nutrient stress affects overall plant fitness.
• Nitrogen acquisition and metabolism is key in plant development.
• Plants have evolved to adapt to nutrient stress.