Chapter 37 Plant Nutrition AP Biology Physiological adaptation

Chapter 37: Plant Nutrition AP Biology

Physiological adaptation Dogs pee on trees…Why don’t trees pee on dogs? NH 3 animal waste AP Biology plant nutrient

Nutritional needs § Autotrophic does not mean autonomous u plants need… § sun as an energy source § inorganic compounds as raw materials w water (H 2 O) w CO 2 w minerals AP Biology

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

For what & from where? C macromolecule synthesis CO 2 O macromolecule synthesis CO 2 H macromolecule synthesis & proton pumps H 2 O N protein & nucleic acid synthesis soil P nucleic acids, ATP, phospholipids soil K stomate control, water balance soil Ca cell wall & membrane structure, regulation soil Mg chlorophyll soil S proteins, enzymes soil AP Biology

Local Long Island soil issues Quartz silica based soils - low in P - can be acid Acid soils bind up mineral ions p. H by adding lime AP Biology Granite

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

Agronomists really dig dirt! The role of soils § Plants are dependent on soil quality u texture / structure § relative amounts of various sizes of soil particles u composition § organic & inorganic chemical components § fertility 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

Soil health as a global issue Not taking care of soil health has far-reaching, damaging consequences 1920’s Dust Bowl u lack of soil conservation u § growing the same crop year after year (wheat) § grazing by cattle § bare ground exposed to wind erosion in winter § drought AP Biology

Soil health as a global issue § Soil conservation & sustainable agriculture u u u maintaining healthy environment sustainable production of food supply economically viable farming industry “A sustainable agriculture does not deplete soils or people. ” – Wendell Berry contour plowing AP Biology cover crops crop rotation

Global issues § soil fertility § erosion § irrigation § forestry destruction AP Biology

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)

Plow it under? Why would you that? Increasing soil fertility § Cover crops u growing a field of plants just to plow them under § usually a legume crop § taking care of soil’s health w puts nitrogen back in soil AP Biology A farmer… outstanding in his field? erosion control, too

Some plant oddities… AP Biology

Parasitic plants § tap into host plant vascular system Indian pipe Mistletoe AP Biology

Plants of peat bogs § High acid environment u most minerals & nutrients bound up & are not available to plants § must find alternative sources of nutrients AP Biology

Carnivorous plants Sundew Venus fly trap Pitcher plant Are they really carnivores? AP Biology

AP Biology Pitcher plant

Uses of peat AP Biology