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Unformatted text preview: B I O L O G Y 1 2 2 3 Plant Nutrition Autotrophic does not mean autonomous B I O L O G Y 1 2 2 3 Needs • Sun as energy source • Inorganic materials as building materials – Water – CO 2 – minerals Fig. 41.3 Plant thrives; test element may not be essential b. Procedure for identifying elements essential for proper plant nutrition Lettuce plant growing in complete nutrient solution or Transplantation Plant grows abnormally; test element is essential Solution lacking one element B I O L O G Y 1 2 2 3 Macronutrients • Needed in large amounts – C arbon – O xygen – H ydrogen – N itrogen – P hosphorus – K potassium – C alcium – Mg Magnesium – S ulphur Macronutrients 41.1 B I O L O G Y 1 2 2 3 Micronutrients • Needed in very small amounts – Co-factors Micronutrients See Table 41.1 Mineral Deficiencies Fig. 41.4 B I O L O G Y 1 2 2 3 Obtaining and Absorbing Nutrients • Root systems allow plants to locate and absorb essential nutrients • Nutrients move into and through the plant body by several routes • Plants depend on bacterial metabolism to provide them with usable nitrogen • Some plants obtain scarce nutrients in other ways B I O L O G Y 1 2 2 3 Root Systems • Extensive root systems are adaptations to limited mineral nutrients – May be more than half of total plant mass – Roots grow as long as plant lives • Roots have mechanisms to increase uptake – Root hairs – Membrane transporters – Mycorrhizae symbiotic with fungi B I O L O G Y 1 2 2 3 15-Feb-10 Gardiner 11 B I O L O G Y 1 2 2 3 Nutrient Movement • Nutrients taken up actively, or passively via transpiration – Apoplastic (xylem) or symplastic...
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