Minerals H2OH2O H2OH2O O2O2 O2O2 CO 2

Control: Solution containing all minerals Experimental: Solution without potassium

Nutrients Macronutrients Micronutrients essential elements plants require them in relatively large amounts Carbon Oxygen Hydrogen Nitrogen Potassium Calcium Magnesium Phosphorous Sulfur plants require them in very small amounts

Healthy Phosphate-deficient Potassium-deficient Nitrogen-deficient

No phosphorus deficiency Beginning phosphorus deficiency Well-developed phosphorus deficiency

Fertilizers Irrigation Erosion Topsoil loss Contour tillage

Nitrogen Fixation Nitrogen-fixing bacteria convert atmospheric N 2 to nitrogenous minerals usable by plants Symbiotic relationship (mutualistic)

Bacteroids within vesicle Nodules Roots Pea plant root. Bacteroids in a soybean root nodule. 5 µm

Mycorrhizae and Plant Nutrition Mycorrhizae mutualistic associations of fungi and roots fungus benefits steady supply of sugar from the host plant host plant benefits fungus increases the surface area for water uptake and mineral absorption

Two Main Types of Mycorrhizae Ectomycorrhizae mycelium of the fungus forms a dense sheath over the surface of the root

Epidermis Mantle (fungal sheath) Fungal hyphae between cortical cells Endodermis Mantle (fungal sheath) Cortex Ectomycorrhizae. 100 µm (colorized SEM)

Endomycorrhizae microscopic fungal hyphae extend into the root

Epidermis Fungal hyphae Cortex Endomycorrhizae. Root hair Endodermis Vesicle Casparian strip Arbuscules Cortical cells 10 µm (LM, stained specimen)

Staghorn fern, and epiphyte. This tropical fern (genus Platycerium) grows on large rocks, cliffs, and trees. It has two types of fronds: branched fronds resembling antlers and circular fronds that form a collar around the base of the fern.

Mistletoe, a photosynthetic parasite. Dodder, a nonphotosynthetic parasite. Indian pipe, a nonphotosynthetic parasite. Dodder Host’s phloem Haustoria

Venus’ flytrap. Pitcher plants.Sundews.