PLANT NUTRITION

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CHAPTER 37

• PLANT NUTRITION

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• 2 THEORIES
• JEAN BAPTISTE VAN HERMONT PLANTS GROW BY
  ABSORBING SOIL
• STEPHAN HALES PLANTS GROW BY ABSORBING AIR

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• HYDROPONICS
• THE USE OF A HYDROPONIC CULTURE MAY ALLOW A
  RESEARCHER TO OBTAIN THE INFORMANTION LEADING TO
  FIGURE OUT THE ESSENTIAL NUTRIENTS NEEDED FOR A
  PLANT TO BE HEALTHY

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• THE ROLE OF SOIL IN PLANT NUTRITION
• TOPSOIL RESULT OF THE ACTIVITY OF LICHENS,
  FUNGI, BACTERIA, MOSSES AND THE ROOTS.. THE
  RESULT CREATES TOPSOIL
• HORIZONS VARIOUS LAYERS OF SOIL
• TEXTURE DEPENDS ON THE PARTICLE SIZE, FROM
  COARSE TO CLAY
• LOAMS THE MOST FERTILE SOIL. MADE OF EQUAL
  AMOUNTS OF SAND, SILT AND CLAY
• HUMUS DECOMPOSING ORGANIC MATERIAL, IT IS
  FORMED BY THE ACTION OF FUNGI AND BACTERIA ON
  DEAD ORGANISMS, FECES AND LEAVES ETC.
• ONE TEASPOON OF SOIL HAS ABOUT 5 MILLION BACTERIA

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• CATION EXCHANGE
• POSITIVELY CHARGED MINERALS ARE MADE AVAILABEL TO
  THE PLANT WHEN H IONSIN THE SOIL DISPLACE THE
  MINERAL IONS FROM THE CLAY PARTICLES

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• SOIL CONSERVATION
• FERTILIZER NITROGEN, PHOSPHOROUS AND POTASSIUM
  (POTASH)
• ORGANIC FERTILIZER MANURE, FISH MEAL, COMPOST.
  THE pH IS IMPORTANT WHEN DEALING WITH SOIL
• IRRIGATION SYSTEMS WATER
• EROSION WIND BREAKERS, TERRACING AND COVER
  CROPPING

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• NITROGEN AS A PLANT NUTRIENT
• ATMOSPHERE IS 80 NITROGEN AND IS NOT USABLE BY
  PLANTS
• NITROGEN GAS MUST BE CONVERTED TO NH4 (AMMONIUM
  ION), OR NO3 (NITRATE) IN ORDER TO BE ABSORBED BY
  THE PLANT

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• NITROGEN FIXATION
• NITROGEN FIXING BACTERIA RESTOCK NITROGENOUS
  MINERALS INTO THE SOIL AND CONVERT N2 TO NH3
• CERTAIN PROKARYOTES ARE RESPONSIBLE FOR NITROGEN
  FIXATION
• NITROGENASE IS THE ENZYME THAT CATALYZES THIS
  REACTION

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• NODULES
• ROOT SWELLINGS COMPOSED OF PLANT CELLS THAT
  CONTAIN NITROGEN FIXING BACTERIA OF THE GENUS
  RHIZOBIUM
• EACH SPECIES OF LEGUME IS ASSOCIATED WITH A
  PARTICULAR SPECIES OF RHIZOBIUM

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• THE FORMATION OF THE NODULE IS A SERIES OF FOUR
  STEPS THAT INVOLVES A SYMBIOTIC RELATIONSHIP WITH
  BACTERIA
• BACTERIA SUPPLIES THE FIXED NITROGEN
• PLANT SUPPLIES FOOD FOR THE BACTERIA
  (CARBOHYDRATE)

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• MYCORRHIZAE PLANTS FLOURISH DUE TO INCREASE
  ABSORPTION OF WATER DUE TO THIS SYMBIOTIC
  RELATIONSHIP

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• PROTEIN YIELDS IN CROPS MUST BE MAINTAINED
• CROP ROTATION RESTORES LOST NITROGEN TO THE SOIL
  TO ALLOW FOR THE MAINTAINENCE OF PROTEIN

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• CARNIVEROUS PLANTS
• FOUND IN NITROGEN POOR ENVIRONMENTS
• PHOTOSYNTHETIC
• SECRETE DIGESTIVE ENZYMES IN THE LEAF
• OBTAIN NITROGEN FROM INSECTS

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• PARASITIC PLANTS
• MISTLETOE PARASITIC TO OAK, ARE PHOTOSYNTHETIC
• DODDER NON PHOTOSYNTHETIC, TAKE ALL THE
  NUTRIENTS FROM THE HOST
• EPIPHYTES NON-PARASITIC
• COMMENSAL RELATIONSHIP WITH THE HOST
• GROW ON OTHER PLANTS
• ABSORB WATER AND MINERALS FROM THE RAIN

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