Plant homeostasis

• plants carry out homestasis, just like animals they need to maintain a constant internal environement
• stomata (guard cells) control the diffusion of gases in and out of leaves

  • means stomata control the entry of carbon dioxide into leaves
• summary of stomata stimuli

  
• increasing light intensity causes stomata to open
• low co2 conc in air spaces causes stomata to open
• darkness causes stomata to close
• high co2 concentration in air spaces makes stomata close
• low humidity makes stomata close
• high temperature makes stomata close
• water stress makes stomata close
• Advantages and disadvantages of when stomata opens

  
• During the day:

  Advantage

  • leaves gain co2 for photosynthesis

  
  

  Disadvantage

  • leaves lose large amounts of water by transpiration
• Closed during day:

  Advantage

  • water is retained inside leaves; important for water stress

  Disadvantage

  • Supply of co2 decreases so the rate of photosynthesis decreases