Plant Mineral Nutrition

Nutrition in Plants

• Definition of Nutrition: the process by which an organism obtains food to provide energy and materials for life-sustaining activities

Modes of Nutrition in Plants

• Autotrophic: organisms that can depend on themselves for building organic nutrients through photosynthesis (e.g. higher plants and algae)
• Heterotrophic: organisms that cannot depend on themselves for building organic nutrients
  • Parasitic: obtain inorganic nutrients from the host plant (e.g. on stem, on root)
  • Saprophytic: obtain inorganic nutrients from dead organic matter (e.g. Agaricus, Rhizopus)
  • Symbiotic: mutually beneficial relationships (e.g. Micorrhiza) or obtain inorganic nutrients from insects (e.g. Insectivorous Plants, Pitcher, Dionea, Drosera)

Plant Mineral Nutrition

• Definition: the study of chemical elements and compounds necessary for plant growth, metabolism, and external supply
• Criteria for essential elements (E.Epstein, 1972):
  • In its absence, the plant is unable to complete a normal life cycle
  • The element is part of some essential plant constituent or metabolite
• Modified criteria (E.Epstein, 2005):
  • The element is part of a molecule that is an intrinsic component of the structure or metabolism of a plant
  • The plant can be severely deprived of the element, exhibiting abnormalities in growth, development, or reproduction

Essential Elements for Plant Growth

• 17 essential elements required for optimal growth and development
• Basic elements required for plant growth:
  • CO2, sunlight, H2O, O2, and essential mineral nutrients
  • Macronutrients: N, P, K, Ca, Mg, S, Zn, Cu, Fe, Mn, B, Mo, Cl, Ni, Co
• Inorganic components of plants: essential and non-essential elements
  • Macronutrients: elements required in large quantities (>0.1% in plant body)
  • Micronutrients: elements required in small quantities