Plant Nutrition AP Biology 2006 2007 Macronutrients Plants

Plant Nutrition AP Biology 2006 -2007

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

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

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

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

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

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

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

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

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

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

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

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

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