Why do Venus flytraps have flytraps? AP Biology Plant Nutrition (Ch 38) AP Biology Physiological adaptation Dogs pee on trees…Why don’t trees pee on dogs? AP Biology Physiological adaptation Dogs pee on trees…Why don’t trees pee on dogs? NH3 animal waste AP Biology plant nutrient Nutritional needs Autotrophic does not mean autonomous plants need… sun as an energy source inorganic compounds as raw materials water (H2O) CO2 minerals AP Biology Macronutrients Plants require these nutrients in relatively large amounts AP Biology C, O, H, N, P, K, Ca, Mg, S Mineral absorption Proton pumps active transport of H+ ions out of cell chemiosmosis H+ gradient creates membrane potential difference in charge drives cation uptake creates gradient cotransport of other solutes against their gradient 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 Take 2 fertilizer pellets & call me in the morning chlorosis = yellowing of leaves Why? What is magnesium’s function? 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 texture / structure relative amounts of various sizes of soil particles composition organic & inorganic chemical components fertility AP Biology Importance of organic matter Topsoil most important to plant growth rich in organic matter So don’t rake your lawn or bag your leaves 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 AP Biology Soil health as a global issue Not taking care of soil health has far-reaching, damaging consequences 1920’s Dust Bowl lack of soil conservation 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 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 manure, compost, fishmeal “Chemical” fertilizers commercially manufactured N-P-K (ex. 15-10-5) 15% nitrogen 10% phosphorus 5% potassium AP Biology What are the political, economic, environmental issues? Nitrogen uptake Nitrates plants can only take up nitrate (NO3-) Nitrogen cycle by bacteria trace path of nitrogen fixation! root AP Biology What will the plant use N for? Soybean root nodules N fixation by Rhizobium bacteria AP Biology symbiotic relationship with bean family (legumes) Plow it under? Why would you that? Increasing soil fertility Cover crops growing a field of plants just to plow them under usually a legume crop taking care of soil’s health puts nitrogen back in soil AP Biology erosion control, too Some plant oddities… AP Biology 2006-2007 Parasitic plants tap into host plant vascular system Indian pipe What are the pros and cons? Mistletoe AP Biology Carnivorous plants Sundew Venus fly trap Pitcher plant Why do they do AP Biology this? In what type of environment would they be found? Figure 37.15c Sundews Pitcher plants Venus flytrap AP Biology AP Biology Pitcher plant Plants of peat bogs High acid environment most minerals & nutrients bound up & are not available to plants must find alternative sources of nutrients AP Biology Mycorrhizae increase absorption Symbiotic relationship between fungi & plant AP Biology symbiotic fungi greatly increases surface area for absorption of water & minerals increases volume of soil reached by plant increases transport to host plant REVIEW 1. How is symbiosis critical to plant survival and evolution? 2. How do plants take in nutrients? 3. Name two critical nutrients, and state what outcome their deprivation would have on plants. AP Biology Any Questions?? AP Biology 2006-2007