AP Biology Plant Nutrition

AP Biology Macronutrients  Plants require these nutrients in relatively large amounts  C, O, H, N, P, K, Ca, Mg, S

AP Biology Micronutrients  Plants require in very small amounts  Cl, Fe, Mn, Bo, Zi, Ni, Mb  primarily cofactors for enzyme function

AP Biology Nutrient deficiencies  Lack of essential nutrients  exhibit specific symptoms  dependent on function of nutrient  dependent on solubility of nutrient

AP Biology Magnesium deficiency  Symptoms  chlorosis = yellowing of leaves  Why? What is magnesium’s function? Take 2 fertilizer pellets & call me in the morning

AP Biology Chlorophyll Why does magnesium deficiency cause chlorosis? The chlorosis shows up in older leaves first, because plant moves Mg + to newer leaves. Why?

AP Biology Importance of organic matter  Topsoil  most important to plant growth  rich in organic matter  humus  decomposing organic material breakdown of dead organisms, feces, fallen leaves & other organic refuse by bacteria & fungi  improves soil texture  reservoir of minerals  organisms  1 tsp. of topsoil has ~5 billion bacteria living with fungi, algae, protists, insects, earthworms, nematodes So don ’ t rake your lawn or bag your leaves

AP Biology Fertilizers  “Organic” fertilizers  manure, compost, fishmeal  “Chemical” fertilizers  commercially manufactured  N-P-K (ex )  15% nitrogen  10% phosphorus  5% potassium What are the political, economic, environmental issues?

AP Biology Nitrogen uptake  Nitrates  plants can only take up nitrate (NO 3 - )  Nitrogen cycle by bacteria  trace path of nitrogen fixation! What will the plant use N for? root

AP Biology Soybean root nodules  N fixation by Rhizobium bacteria  symbiotic relationship with bean family (legumes)

AP Biology Mycorrhizae (“fungus roots”)  symbiotic associations between the roots of plant species & fungi  Fungus gets sugar from plant  Plant’s surface area for uptake of water, phosphate, and other minerals increased by mychorrhizae

AP Biology Parasitic plants  tap into host plant vascular system for sugar and minerals Indian pipe Mistletoe

AP Biology Carnivorous plants Obtain some N and minerals by killing and digesting other small animals Pitcher plantVenus fly trap Sundew

AP Biology Carnivorous Plants  Live in high acid environment (acid bogs)  Soils here are poor in nitrogen and other nutrients