CIE IGCSE Biology

Revision Notes

16.1.3 Germination

Factors Affecting Germination

  • Germination is the start of growth in the seed
  • Three factors are required for successful germination:
    • Water – allows the seed to swell up and the enzymes in the embryo to start working so that growth can occur
    • Oxygen – so that energy can be released for germination
    • Warmth – germination improves as temperature rises (up to a maximum) as the reactions which take place are controlled by enzymes
  • As carbon dioxide is not necessary for germination but also does not inhibit it, it makes no difference whether it is present or not

Investigating Germination

  • Set up 4 boiling tubes each containing 10 cress seeds on cotton wool
  • Set each test tube as shown in diagram below
  • Leave tubes in set environment for a period of time: A, B and C incubated at 20°C; D placed in a fridge at 4°C
  • Compare results and see which tube has the greatest number of germinated seeds

 

Conditions required for germination, IGCSE & GCSE Biology revision notesConditions required for germination

 

Conditions required for germination – results:

Conditions for germination results table, IGCSE & GCSE Biology revision notes

Author: Jenna

Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.
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