Page 11 - Chapter 07

Materials Part 3: Investigation of the necessity of carbon dioxide
Required
Potted plant, split cork, wide mouth bottle/flask, potassium hydroxide (KOH) solution,
beaker, test tube, ethanol, iodine solution, dropper, burner, petri dish, water, vaseline

Leaf attached
with plant

Cork

Flask No CO2

Potassium hydroxide
solution

Procedure Stand for flask

Figure 7.3.4: Experiment setup to investigate the necessity
of CO2 in photosynthesis

ΠDe-starch the potted plant by placing it in a dark place for about 2-3
days.

 Add potassium hydroxide solution into the ! C A U T I O N S

wide mouth bottle (KOH will absorb all the • Don't leave any
CO2 present in the bottle).
space between cork

sections and the

Ž Cut a cork length wise into two pieces. leaf.

 Pass leaf of the potted plant (without detaching) through the cut section
of the cork in such a way that half portion of the leaf remains out of the
bottle.

 Make the apparatus airtight by applying vaseline on the cuttings of
cork.

‘ Place the apparatus in bright sunlight for a few hours for
photosynthesis.

’ Remove this leaf from the plant.

“ Apply starch test to the leaf.

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