plant nutrition

• cuticle: protective layer that allows light to enter the leaf; it is waterproof in order to prevent waterloss due to evaporation
• upper epidermis: produces waxy cuticle; allows light to enter the leaf

  • does not contain chloroplasts
  • made of wax to prevent infection within the plant
  • wax also makes sure that there is minimal water loss while still a good supply for sunlight entering the leaf
• palisade mesophyll: allows many chloroplasts to be packed together closely

  • absorbs all the available light
• spongy mesophyll: loosely packed cells that have air spaces for gas exchange to occur

  • have large surface area to increase diffusion of carbon dioxide and oxygen
• air spaces: increases surface area for gas exchange; allows gas exchange to occur more easily
• xylem: allows water to be exported across the plant
• phloem: helps transport amino acids and sucrose across the plant
• lower epidermis: large surface area + contains stomata and guard cells to allow carbon dioxide to enter and oxygen to leave
• stomata: controls gas exchange
• guard cells: help minimise water loss
• limiting factor: a factor that prevent the rate of something from increasing
• hydrogen carbonate indicator: used to estimate the concentration of carbon dioxide in the water

  • low = magenta
  • normal = red
  • yellow or orange = high