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Chapter 37 Plant Nutrition. Biology 102 Tri-County Technical College Pendleton, SC. Macro versus Micronutrients. Macronutrient is nutrient required by plant in large amounts Micronutrient is nutrient required by plant in small amounts Micronutrients:
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Chapter 37 Plant Nutrition Biology 102 Tri-County Technical College Pendleton, SC
Macro versus Micronutrients • Macronutrient is nutrient required by plant in large amounts • Micronutrient is nutrient required by plant in small amounts • Micronutrients: • Carbon (CO2)-major component of plant’s organic compounds • Oxygen (CO2)-major component of plant’s organic compounds
Macronutrients, cont. • Hydrogen (H2O)-major component of plant’s organic compounds • Nitrogen (NO3-; NH4+)-component of nucleic acids, proteins, hormones, and coenzymes • Sulfur (SO42-)-component of proteins & coenzymes
Macronutrients, cont. • Phosphorous (H2PO4-; HPO42-)-component of nucleic acids, phospholipids, ATP, & several coenzymes • Potassium (K+)-cofactor that functions in protein synthesis, major solute functioning in water balance, & operation of stomata • Calcium (Ca2+)-formation and stability of cell walls, maintenance of membrane structure and permeability, activates some enzymes, regulates many responses of cells to stimuli
Macro and Micro • Magnesium (Mg2+)-component of chlorophyll, activates many enzymes • MICRONUTRIENTS: • Chlorine (Cl-)-required for water-splitting step of photosynthesis, functions in water balance • Iron (Fe3+; Fe2+)-component of cytochromes, activates some enzymes
Micronutrients, cont. • Boron (H2BO3-)-cofactor in chlorophyll synthesis, may be involved in carbohydrate transport and nucleic acid synthesis • Manganese (Mn2+)-active in formation of amino acids, activates some enzymes, required for water-splitting step of photosynthesis • Zinc (Zn2+)-active in formation of chlorophyll and activates some enzymes
Micronutrients, cont. • Copper (Cu+; Cu2+)-component of many redox and lignin-biosynthetic enzymes • Molybdenum (MoO42-)-essential in nitrogen fixation and cofactor that functions in nitrate reduction • Nickel (Ni2+)-cofactor for enzyme functioning in nitrogen metabolism
Micronutrient Why’s? • Most micronutrients function as cofactors of enzymatic reactions • Because micronutrients generally play catalytic roles that plants need only minute quantities of these elements • Example: only 1 molybdenum atom for each 16 million atoms of hydrogen in dried plant material
Plants and Nitrogen • Plants require nitrogen to produce proteins, nucleic acids, and other organic molecules • They CANNOT use nitrogen in gaseous form (N2) • To be used, must be in form of ammonium (NH4+) or nitrate (NO3-) • Plants acquire most of their nitrogen in the form of nitrate (NO3-)
Plants and Nitrogen, cont. • Nitrate produced in soil by nitrifying bacteria • They oxidize ammonia/ammonium • Other species of nitrogen fixing bacteria live in plant roots (mutualistic symbiotic relationship) • Nitrogen absorbed by plant is incorporated into organic compounds
Miracle Grow or thereabouts… • Ever purchase a bag of triple 13? • No, how about triple 10? • 13-13-13 or 10-10-10 • Not brain surgery…is by weight so close • Lists contents in order of: Nitrogen, phosphorous, and potassium • N-P-K • 21-0-0 (Oh yeah…but….)
Nitrogen Fixation • Few species of bacteria possess enzyme that will convert nitrogen gas to ammonia (N2 NH3) • Essential to life on this planet • Cyanobacteria and Rhizobium • Rhizobium “infects” roots of plants causing nodulation • These nodes are site of bacteria nitrogen fixing
Bits and Pieces… • Mutualistic symbiotic relationship • Mycorrhizae is mutualistic relationship between fungus and plant roots • Increases absorption of water and minerals (especially phosphorus) • Can be ECTO or ENDO • (This should be a review from Bio 101)
Heterotrophic/Carnivorous Plants • Some plants have lost ability to sustain themselves by photosynthesis • Mistletoes, dodders, and Indian pipe • Kind of ify for mistletoe but…. • Extract nutrients from hosts by absorptive organs called haustoria • Approximately 450 plant species are carnivorious
H/C Plants, cont. • Do not live by photosynthesis alone • Venus fly trap, sundews, & pitcher plants • Most live in acidic environments • Difficult for decay-causing organisms to break down bodies of dead organisms • Hence, not much recycling • These plants evolved way to supply their nitrogen (and phosphorous) needs by “eating protein”