Plant Nutrition- Ch. 37 Stephanie Ellis

Essential Nutrients All minerals a plant needs to survive and reproduce Macronutrients are needed in relatively large amounts Micronutrients are needed in relatively small amounts

Soil Composition Most nutrients found in Topsoil Horizons Sand, silt, clay Loams are the most fertile type of soil

Obtaining Minerals from Soil + Charged minerals adhere to - charged clay particles Cation Exchange displaces the + mineral ions with H+ ions secreted by the plant’s roots

Obtaining Nitrogen Nitrogen is not available directly from the atmosphere Nitrogen fixing bacteria provide N in the form of ammonium

Nitrogen Fixation N2 + 8 e- + 8 H+ + 16 ATP  2 NH3 + H2 + 16 ADP + 16 Pi This reaction is catalyzed by the enzyme complex nitrogenase.

An Adaptation for N Fixation Legume roots have a symbiotic relationship with Rhizobium Bacteria congregates in root nodules

Mycorrhizae Symbiotic relationship between fungi and plant roots Plant gives sugars to fungus Fungus gives PO4, other minerals, growth factors, antibiotics to plant

Ectomycorrhizae Endomycorrhizae

Parasitism

Carnivorous Plants

Mineral Deficiencies Effects of a deficiency depend on… 1. Role in plant nutrition 2. Mobility

Sustainable Agriculture Goal to prevent mineral deficiencies in an economical and ecological manner 1. Fertilization 2. Irrigation 3. Preventing Erosion

Plant Nutrition… Goals for the Future Increase plants’ protein production by adding more N compounds This would greatly reduce malnutrition in 3rd world countries

Possible Methods Commercial Fertilization to add N compounds to soil Hydroponic farming to provide N compounds Synthesized catalysts modeled after Rhizobium’s nitrogenase