_ 87 _ PHOTOSYNTHESIS. 



6. The necessity of carbon dioxide for the output of oxygen. 



27. The intake of carbon dioxide by an aquatic plant in the light. 



(a) Demonstration of the colours assumed by an indicator in tap-water and in 



water saturated with carbon dioxide. 



(b) Aquatic plants are seen in two glass tubes of \vater each containing the 

 indicator and carbon dioxide in solution. One tube is exposed to sunlight 

 and the other kept in darkness. 



28. Formation of starch inside chloroplasts in the light. Chloroplasts of 

 leaves which have been fixed and stained with iodine. 



(a) From a plant which had been exposed to sunlight. 



(b) From a plant which had been kept in darkness. 



12 



