chapter 10

• The seed germination have 3 process

  • activation
  • digestion
  • seedling growth
• • During seed germination, imbibition of water occurs .The water
• Seed germination

  1. Imbibition of water

  2. Water diffuses through micropyle

  3. Increase in seed volume

  4. Testa breaks

  5. Activation of embryo to release enzymes
• Imbibition


  Absorption of water by seeds
• Hydrolytic enzyme


  Enzyme that breaks down proteins in the aleurone cell into amino acids
• Gibberellic acid


  Hormone that directs DNA in aleurone cell to synthesize enzymes
• Enzyme synthesis in aleurone cell

  1. Gibberellic acid diffuses into aleurone layer

  2. Directs DNA to synthesize alpha-amylase

  3. Synthesis of other hydrolytic enzymes such as protease
• Alpha-amylase


  Enzyme that hydrolyses starch to maltose
• Hydrolysis of maltose

  Maltose is hydrolysed to glucose with the help of maltase
• Glucose is transported to embryo cell for cellular respiration
• Cellular respiration supplies energy for developing embryo
• The germination starts with the emergence of radicle
• Embryonic development


  1. Double fertilisation in embryo sac

  2. Zygote develops into embryo

  3. Triploid primary endosperm nucleus develops into endosperm

  4. Integument cell of ovule develops into testa

  5. Zygote undergoes mitosis to form apical cell and basal cell

  6. Apical cell develops into proembryo

  7. Basal cell develops into suspensory cell

  8. Proembryo undergoes globular stage

  9. Proembryo undergoes heart stage

  10. Proembryo undergoes torpedo stage

  11. At torpedo stage, cotyledon, shoot and root meristem are formed

  12. Shoot meristem undergoes mitosis and develops into plumule

  13. Plumule develops into shoot

  14. Root meristem undergoes mitosis and develops into radicle

  15. Radicle develops into root
• Mature embryo in monocotyledon plant


  • Consists of one shoot
  • One root
  • One cotyledon