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Unformatted text preview: Nutrition in Plants
Lecture 15 Chapter 37 1 What Nutrients do plants need? Plants like all organisms continuously exchange energy and materials with the environment. CO2 (day) and O2 (night) from the air All other nutrients from the soil 2 3 Hydroponics Aerated water can substitute for soil for many plants Allows total control of nutrients
4 Soils Breakdown products of rocks (clay & sand) Breakdown products of dead organisms (especially plants and microorganisms) Living organisms Can range from <1% to nearly 100% 1x109 (1 billion) bacteria per cc 1 km of fungal hyphae/10 cc 5 Most roots cells obtain O2 from soil air or soil water Most metal ions are bound to soil particles Roots secrete CO2 from respiration and H+ 6 Mycorrhizae Many plants benefit from symbiotic relationships with fungi mycorrhizae The fungi provide the plant with minerals and the plant provides the fungi sugar 7 Nitrogen The atmosphere is 80% N2 Nitrogen fixing soil bacteria and cyanobacteria (bluegreen algae) Lightning (<10%) Mankind
8 Plants cannot use it Plants use NH4+ or NO3 Nitrogen cycle NO3 is easily leached out of soils
9 Eutrophication of lakes and streams Most, if not all of Iowa streams and lakes
Gulf of Mexico Experiment 10 "Nitrogen fixing" plants Many legumes (beans, clover, alfalfa, acacia trees) do not require soil nitrogen Symbiotic relationship with nitrogen fixing bacteria (especially Rhizobium) Root "nodules" Bacterial nurseries 11 12 The plant grows all needed structures Stele 13 Other adaptations for obtaining nutrients Carnivorous plants Parasitic plants 14 D:\Unit_6\Chapter_37\Instructor Resources\Mo D:\Unit_6\Chapter_37\Instructor Resources\M 15 ...
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