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Unit: Plant Nutrition Nutritional Needs of Plants

Unit: Plant Nutrition Nutritional Needs of Plants. Plants and mineral nutrients: Plants require certain elements in order to grow and stay healthy. 16 Elements essential to plant growth:. Macronutrients: Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N) Phosphorous (P) Potassium (K)

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Unit: Plant Nutrition Nutritional Needs of Plants

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  1. Unit: Plant Nutrition Nutritional Needs of Plants

  2. Plants and mineral nutrients: Plants require certain elements in order to grow and stay healthy. 16 Elements essential to plant growth: Macronutrients: Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N) Phosphorous (P) Potassium (K) Sulfur (S) Calcium (Ca) Magnesium (Mg) Micronutrients: Chlorine (Cl) Iron (Fe) Manganese (Mn) Boron(B) Zinc (Z) Copper (Cu) Molybdenum (Mo)

  3. What makes an element essential? There are 3 established criteria for an “essential element”: • The plant cannot complete it’s life cycle without the element. 2. Action of the element must be specific- no other element can substitute for it. 3. The element must be directly involved in the nutrition of the plant.

  4. Macro vs. Micro • Macronutrients: nutrients required in large amounts and absorbed from the soil or hydroponic solution. • Micronutrients: nutrients required in small amounts and absorbed from a soil or a hydroponic solution. • Does NOT imply importance. All of the essential nutrients are required for growth and function.

  5. Mobile vs. Immobile These nutrients are further divided into the mobile and immobile nutrients. Mobile: A plant will always supply more nutrients to its younger leaves than its older ones, so when nutrients are mobile, the lack of nutrients is first visible on older leaves. Immobile: When a nutrient is less mobile, the younger leaves suffer because the nutrient does not move up to them but stays lower in the older leaves.

  6. Macronutrients • Carbon (atmosphere) • Hydrogen (Water) • Oxygen (atmosphere) These 3 nutrients make up 95% of a plants fresh tissue. Typically not limiting factors except for: Drought Disease Extreme cold Poor drainage

  7. N - Nitrogen • Function: Nitrogen stimulates growth, increase of fruit production and gives plants a healthy green color. • Toxicity: dark green plant with restricted root system and fruit set. • Deficiency: Mobile. Growth restricted. Leaves become light green and yellow then die.

  8. K - Potassium: • Function: • Catalyst/activator for enzymes • Encourages vigor/health • Deficiency: Highly mobile – older growth • Poor growth, chlorosis, necrosis; reduced gas exchange • Toxicity: Hi K may cause Ca, Mg, Mn, Zn, Fe deficiencies

  9. P - Phosphorus: • Function: for the energy molecules: ATP, ADP, AMP • Deficiency: Very mobile (old growth) • Lower leaf surfaces turn purple • Leaves curl downward • Poor leaf, root, flower development • Toxicity: Not usually a problem

  10. Ca -Calcium: • Function: • As an activator of enzymes • Plant strength & vigor • As a “neutralizing” agent • Deficiency: Immobile (new growth) • Misshapen, poor or no growth • Blossom end rot of fruit • Toxicity: Not usually a problem

  11. (Mg) Magnesium: • Function: • “heart” of the chlorophyll molecule • Enzyme activator (ATP, DNA, RNA) • Deficiency: Highly mobile • Older leaf interveinal chlorosis • Upturned leaves • Toxicity: • Not known

  12. Sulfur: • Function: • Form “disulfide bonds” that aide in the folding of proteins and effect their function • Deficiency: Moderately mobile • Less chlorophyll  chlorosis and • purplish veins in mid/young leaves • Thin, brittle stems • Toxicity: • Red. Growth, interveinal chlorosis, leaf burn

  13. Let’s review the macros…(all result in poor growth) Mobile Functions Def. Symptoms N Y protein, RNA, DNA, Chl chlorosis, necrosis P Y ATP, etc. purple underleaf K Y Catalyst/activator for enzyme red. Transpiration Ca N cell walls, enzyme act. poor “new” growth blossom end rot in fruit Mg Y Chlorophyll, enzyme act. Interveinal chl. brittle upturn leaf S Mod 2 amino acids “mid/new” growth: chlorosis, purple veins, thin brittle stems

  14. Micronutrients: • Iron: (Fe) • Function: • Involved in chlorophyll & protein synthesis and respiration • Deficiency: Immobile • New growth interveinal chlorosis • Toxicity: • If over-apply foliar  necrotic spots

  15. Manganese: (Mn) • Function: • Enzyme activator (chl, RNA, DNA) • carbohydrate metab., O2 prod. • Deficiency: Relatively immobile • Newer growth interveinal chlorosis • Necrotic spots/leaf drop • Upward leaf curl • Toxicity: • Reduced growth • Hi Mn  Low Fe and interveinal chlorosis

  16. Boron: (B) • Function: • Related to metabolism of Ca, K • Regulates carbohydrate • Involved in RNA synthesis • Deficiency: Mobile in leaf; not in plant • Stems: abnormal/slow growth, brittle • Shoot/root die back • Young leaves: thick, curled • Low flowering, fruiting; fruit rots • Toxicity: • Def. sym. + leaf tip chlorosis/necrosis

  17. Zinc: (Zn) • Function: • Enzyme activator • Synthesis of proteins, hormones, • RNA, DNA • Deficiency: Not very mobile • Abnormal and stunted growth • Leaves: interveinal chlorosis, necrosis • Toxicity: • Similar to def. symp.

  18. Copper: (Cu) • Function: (70% of Cu in leaf in chloroplasts) • Chlorophyll synthesis • Deficiency: Immobile • Leaf stunting, twisting; dark green • Reduced turgor (firmness) • Reduced flowering/fruiting • Toxicity: Do not use Cu tube/fixtures • Overall stunting; thick, dark roots

  19. Molybdenum: (Mo) • Function • Involved in carbohydrate metabolism. • Deficiency: Mobile • Leaf interveinal chlorosis, mottling, scorching, inward cupping • Severe: puffy leaf areas & stunting • Toxicity: • Not usually seen… • Leaves can turn yellow

  20. Chlorine: (Cl) • Function: • Enzyme activator • Promotes healthy growth of plants • Hi NaCl  stress  flavor, nutrition • Deficiency: Mobile • Leaf chlorosis then necrosis • Low transpiration, wilting • Plant stunting, die back • Toxicity: Leaf tip burn.

  21. Let’s review the micros: ** Some are mobile, some are not ** ALL are involved in plant metabolism Enzyme activators Parts of enzymes In electron transfer As oxygen carriers Invovled in synthesis/metabolism of proteins, hormones, RNA/DNA, carbohydrates, chlorophyll, ion balance, etc. ** KEY: mainly move around assisting in reactions, etc. Therefore, not needed in large amounts for “structure”.

  22. Other nutrients: Found in some but not all plants; possibly required by those plants Sodium (Na) C4 plants Silicon (Si) C4 & CAM Cobolt (Co) N-fixing bacteria Vanadium (V) Essential in green algae; toxic in hp in hi conc Iodine (I) Stimulates growth in low conc; toxic in hi conc Bromine (Br) Can substitute for Cl Fluorine (F) Toxic; some plants accumulate; hi in teas! Aluminum (Al) Req’d for tea bush; toxic for most plants Nickel (Ni) Maybe req’d for N-fixers; toxic for other plants Selinium (Se) In milk vetches; toxic to most plants

  23. Pictures from this presentation can be found at: www.plantphys.net/_article.php?ch=t&id=289 Plant Physiology online: Chapter 5.1 Visual symptoms of nutrient deficiencies in plants Dr. Wade Berry, UCLA

  24. Questions?

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