Plant Nutrition

• Nutrition

  • refers to any substance required for the growth and maintenance of an organism.
• Two types of organisms based on the mode of nutrition:

  1. Autotrophs
  2. Heterotrophs
• Autotrophs

  • organisms that obtain energy from sunlight and chemicals to produce their own food.
• Heterotrophs

  • organisms that cannot make their own food and obtain their energy from other organisms.
• Essential Nutrients in Plants

  • Basic Nutrients
  • Macronutrients
  • Micronutrients
• Basic Nutrients

  • Carbon (C)
  • Hydrogen (H)
  • Oxygen (O)
• Macronutrients

  • Nitrogen (N)
  • Phosphorus (P)
  • Potassium (K)
  • Sulfur (S)
  • Magnesium (Mg)
  • Calcium (Ca)
• Micronutrients

  • Iron (Fe)
  • Manganese (Mn)
  • Zinc (Zn)
  • Copper (Cu)
  • Boron (B)
  • Molybdenum (Mo)
  • Chlorine (Cl)
  • Nickel (Ni)
• Specialized Absorptive Structures

  1. Root Hairs
  2. Root Nodules
  3. Mycorrhizae (Mycorrhiaza)
• Root Hairs

  • slender extensions of specialized epidermal cells that greatly increase the surface area available for absorption.
• Root Nodules

  • localized swellings in the roots of certain plants where bacterial cells exist symbiotically with the plant. The bacteria help the plant fix nitrogen and in turn, the bacteria can utilize some organic compounds provided by the plant.
• Mycorrhizae

  • a symbiotic interaction between a young root and a fungus. The fungus obtains sugars and nitrogen-containing compounds from root cells while the plant can get some scarce minerals that the fungus is better able to absorb from the soil.
• Routes for the Absorption of Water and Minerals Across Plant Roots:

  1. Apoplastic Route
  2. Symplastic Route
• Apoplastic Route

  • uptake of soil solution by the hydrophilic walls of root hairs provide access to the apoplast.
• Symplastic Route

  • minerals and water that cross the plasma membrane of root hairs can enter the symplast.