Wednesday, March 21, 2012

LC Biology Experiments - Use starch agar plates to show digestive activity during germination

Soak broad beans in distilled water for 2 days
Swab lab bench with disinfectant
Label 1st sterile plate ‘Raw’, 2nd ‘boiled’. Initial and date
Kill two of the seeds by boiling for 5 mins (control)
Split each seed in half to separate the cotyledons
Sterilise all seeds by soaking in disinfectant for 10 mins
Rinse seeds twice in sterilised water
Using a sterilised forceps place seed halves face down on the appropriate agar plate
Re-flame forceps and re-swab bench
Incubate plates upright at 18-20C for 48 hrs
Remove seeds
Flood plates with iodine and leave for 2mins
Pour off Iodine solution
Note pattern of starch digestion by holding plate up to light
A pattern should appear where raw seeds germinated and digested starch on agar plate. The boiled seeds should not have germinated as enzymes required should have been denatured. This plate should be predominantly blue/black

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