6. Plant nutrition

• Photosynthesis: chemical process that occurs in the leaves of greens plants and uses energy from light to make food

  6CO2 + 6H2O → C6H12O6 + 6O2
• Stomata are pores on the underside of a leaf that allow the diffusion of carbon dioxide into the leaf.
• Veins contain the tissues that transport food and water within a leaf.
• Spongy mesophyll is a layer of cells with air spaces between them.
• A waxy cuticle is a transparent layer on the top of a leaf.
• The upper epidermis is a single layer of flat cells covering the top surface of the leaf.
• Palisade cells are a layer of long cylindrical cells just under the upper epidermis.
• Guard cells control the closing and opening of the stomatal pores.
• The lower epidermis is a single layer of flat cells covering the bottom surface of the leaf.
• Chloroplasts are small structures within the cells where photosynthesis takes place.
• Leaf structure:

  A) cuticle

  B) upper epidermis

  C) chloroplasts

  D) vacuole

  E) vein

  F) lower epidermis

  G) palisade cell

  H) spongy mesophyll

  I) guard cells

  J) stomata

  K) cuticle

  
• Limiting factor: any factor that slows down the rate of reaction

  • light intensity (always limiting factor until peak)
  • carbon dioxide concentration (always limiting factor until peak)
  • temperature - if exceeds beyond optimum = denatures
• Effects of:

  • nitrate ions - makes protein absorbed by roots
  • magnesium ion - making chlorophyll (deficiency = discolored leaves)