plant nutrition. where do plants get their nutrients?

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Plant Nutrition Slide 2 Where do Plants get their nutrients? Slide 3 PLANT: A SUGAR FACTORY Slide 4 NUTRIENTS AVAILABILITY AND SOIL The relative availability of nutrients to plant roots depends on the pH level of the soil. Slide 5 Plant Nutrients Content in % Compared to Nitrogen Slide 6 Average Composition of Plant Slide 7 VISUAL SYMPTOMS ON LEAVES When inspecting plants for symptoms of nutrient disorders, compare plants displaying symptoms with normal ones and examine new and older leaves. OLDEST LEAVES: nutrient deficiencies generally appear first in the oldest leaves when nitrogen, phosphorus, potassium, and magnesium are limiting. These nutrients move from one part of the plant to another as needed. YOUNGER LEAVES AND TERMINAL BUDS: show a deficiency when sulfur, iron, calcium, zinc copper, boron, manganese or chlorine are limiting. These nutrients do not readily move about in the plant. Slide 8 Nutrients Deficiency Symptoms on Leaves The most common symptoms of nutrient deficiency are stunted growth and leaf discoloration. The position of the symptoms (distal, basal or intermediate) depends on the mobility of the nutrient inside the plant (young leaves competing with oldest leaves) Slide 9 Mobile Nutrients - Identification Key Slide 10 Immobile Nutrients Identification Key Slide 11 Limiting Nutrient Theory Slide 12 Fertilizer Needs related to Soil Content Slide 13 Organic Fertilizers Macronutrients Content Analysis of Organic Fertilizers Manure%N%P %K Cow 2,0 2.32,4 Horse1.70.71,8 Sheep4,0 1.43,5 Poultry4,0 2,0 Slide 14 How Plant reacts to Fertilizers Slide 15 Nutrients Removal: Apple N (KG)P (KG)K (KG)Mg (Ca)Ca (KG) Nutrient removed per ton apple 0.50.11.10.05 Nutrient removal at 50 tons/ha 255552.5 Nutrient incorporated into trees/ha 20415245 Total nutrient consumed 50t/ha 459704.547.5 Slide 16 Slide 17 Nitrogen Nitrogen is a building block of plant protein. It is an integral part of chlorophyll and is a component of amino acids, nucleic acids and coenzymes. Most nitrogen in the soil is tied up in organic matter. It is taken up by plants as nitrate (NO3-) and ammonium (NH4+) ions from inorganic nitrate and ammonium compounds. These compounds can enter the soil as a result of bacterial action (nitrogen fixation), application of inorganic nitrogen fertilizer, or conversion of organic matter into ammonium and nitrate compounds. Not all nitrates in the soil are taken up by plants. Nitrates can be leached beyond the root zone in sandy soils or converted to nitrogen gas in wet, flooded soils. Nitrogen fixation (from atmosphere) by soil microbes immobilizes nitrogen, making in available for later use by plants. Slide 18 Nitrogen Hints Slide 19 Most plants depend on bacteria to supply nitrogen Slide 20 Symbiotic Nitrogen Fixation (bacteria hosted inside roots nodules) Slide 21 Nitrogen Inputs/Outputs Slide 22 Agriculture and overall Nitrogen Balance Slide 23 Nitrogen from Fall to Springtime Slide 24 Nitrogen Status in Soil in October and March Slide 25 Nitrate and Leaching Slide 26 Nitrification and Denitrification Slide 27 Common N Deficiency Slide 28 N Deficiencies Soybean Wheat Rice Maize Slide 29 Phosphorus Plants use phosphorus to form the nucleic acids DNA and RNA and to store and transfer energy. Phosphorus promotes early plant growth and root formation through its role in the division and organization of cells. Phosphorus is essential to flowering and fruiting and to the transfer of hereditary traits. Phosphorus is adsorbed by plants as H2PO4-,HPO4-2 or PO-3, depending upon soil pH. The mobility of phosphorus in soil is low, and deficiencies are common in cool, wet soils. Phosphorus should be applied to fields and gardens before planting and should be incorporated into the soil. This is especially important for perennial crops. Application rates should be based on soil testing. Slide 30 P hints Slide 31 P Deficiencies Alfalfa Rice Corn Wheat Slide 32 P Deficiency in Maize and Grape Slide 33 Potassium Potassium is necessary to plants for translocation of sugars and for starch formation. It is important for efficient use of water through its role in opening and closing small apertures (stomata) on the surface of leaves. Potassium increases plant resistance to diseases and assists in enzyme activation and photosynthesis. It also increases the size and quality of fruits and improves winter hardiness. Plants take up potassium in the form of potassium ions (K+). It is relatively immobile in soils but can leach in sandy soils. Potassium fertilizer should be incorporated into the soil at planting or before. Application rates should be based on a soil test. Slide 34 K Deficiencies Grape Alfalfa Corn Slide 35 Calcium Calcium provides a building block (calcium pectate) for cell walls and membranes and must be present forthe formation of new cells. It is a constituent of important plant carbohydrates, such as starch and cellulose. Calcium promotes plant vigor and rigidity and is important to proper root and stem growth. Plants adsorb calcium in the form of the calcium ion (Ca+). Calcium needs can be only determined by soil test. In mostcases calcium requirements are metby liming the soil. Potatoes are an exception; use gypsum (calcium sulfate) on potatoes to avoid scab disease if calcium is needed. Gypsum provides calciumto the soil but does not raise the pHlevel ofthe soil. Keeping pH low helps prevent growth of the bacteriathat cause scab disease. Slide 36 Calcium Hints Slide 37 Magnesium Magnesium is a component of the chlorophyll molecule and is therefore essential for photosynthesis. Magnesium serves as an activator for manyplant enzymesrequiredfor sugar metabolism and movement and for growth processes. Plants take up magnesium as the Mg+2 ion. Slide 38 Magnesium Hints Slide 39 Magnesium Deficiencies Maize Cotton Slide 40 Zinc Zinc is an essential component of several enzymes in plants. It controls the synthesis of indoleacetic acid (ANA), an important plant growth regulator, and it is involved in the production of chlorophyll and protein. Zinc is taken up by plants as the zinc ion (Zn+2). Zinc deficiencies are more likely to occur in sandy soils that are lowin organic matter. High soil pH, as inhigh-limesoils, thesolubilityof zinc decreases and it becomes less available. Zinc and phosphorus have antagonistic effects in the soil. Therefore zinc also becomes less available in soils that are high in phosphorus. Wet and cold soil conditions can cause zinc deficiency because of slow root growth and slow release of zinc from organic matter. Slide 41 Zinc Slide 42 Zinc Deficiencies in Apple Slide 43 Iron Iron is taken up by plantsas ferrous ion (Fe+2). Iron is required for the formation of chlorophyll in plant cells. It serves as an activator for biochemical processes such as respiration, photosynthesis and symbiotic nitrogen fixation. Turf, ornamentals and certain trees are especially susceptible to iron deficiency (Quince, Peach, Kiwi) Symptoms of iron deficiency can occur on soils withpH greater than 7.0. Specific needs for iron can be determined by soil test, tissue test and visual symptoms. Slide 44 Slide 45 Mycorrhizae Most plants have mycorrhizae Slide 46 Some Plants are Parasitic Dodder on Pickleweed Mistletoe on an Oak Slide 47 Carnivorous Plants Venus Fly Trap Round leafed Sundew Slide 48 Improving Protein Content Slide 49 Genetic Engineering There are two main techniques used: Slide 50 Products of Plant Biotechnology Delayed ripening tomatoes Herbicide resistant canola, soybeans, cotton, and other crops Insect resistant corn, potatoes, and other crops Golden Rice (vitamin A and beta-carotene enriched) Slide 51 Plants have hormones Hormones Slide 52 Plant Hormones What is a hormone? It must meet these criteria: An endogenous organic compound Active at very low concentrations Produced in one tissue Transported from the site of synthesis to the tissue in which it acts Affects growth, development and physiological responses (it is not a nutrient or vitamin) Slide 53 Plant Hormones Auxin Differentiation Elongation Growth responses Gibberellins (GA) Elongation Cell division Seed germination Cytokinins Cell enlargement Differentiation Abscisic Acid (ABA) Inhibitor Responses to stress Stomatal opening Ethylene Fruit ripening Flowering Flower senescence Others jasmonic acid, brassinolide, salicylic acid Slide 54 Auxin Controls cell elongation and expansion Involved in phototropic and gravitropic responses growth of shoots towards light downward growth of roots (response to gravity) Suppresses growth of axillary buds Stimulates root initiation and growth Stimulates fruit growth Slide 55 Phototropism Slide 56 Phototropism Experiments Slide 57 More phototropism experiments Slide 58 Auxin Slide 59 Effect of Auxin Slide 60 How does Auxin work? Slide 61 Terminal Bud Removal Slide 62 Branching of shoots Where do branches come from? Develop from axillary buds Buds are present within leaf axils on the stem (stems have buds) Slide 63 Branching of shoots Axillary buds contain a meristem that is usually inactive apical dominance growth at the apex suppresses growth of lateral shoots Why are axillary buds normally dormant? Active apical bud Dormant axillary buds Slide 64 Branching of shoots Auxin is produced in shoot apex and transported down the plant stem The concentration of auxin is high close to the shoot apex Auxin concentration is lower in tissues further away from the apex Auxin produced in shoot apex High [auxin] Low [auxin] Slide 65 Branching of shoots High concentrations of auxin suppress growth of axillary buds near the apex Further away from the apex, where the auxin concentration is lower, growth of axillary buds is not inhibited These buds develop and grow, forming branches Auxin produced in shoot apex High [auxin] Low [auxin] Slide 66 Branching of shoots The strength of apical dominance varies among plant specie

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