

_ 89 - PHOTOSYNTHESIS. 



33. Leaf containing a red non-photosynthetic pigment. -The presence of 

 chlorophyll in addition is shown by its solution in alcohol. 



34. Necessity of light for the formation of chlorophyll. 



(a) Seedlings grown in light. 

 (6) Seedlings grown in darkness. 



(c) Seedlings grown in darkness and exposed to light a short time before the 

 demonstration. 



35. Destruction of chlorophyll by intense light. Solutions of chlorophyll 

 before and after having been exposed to direct sunlight. (Note that the chlorophyll is 

 exposed to the sun's rays behind a screen formed by a solution of alum. This stops the 

 heat-rays.) 



36. (Protective movement of chloroplasts in response to intense illumina- 

 tion. Cells seen under the high power after having been (a) exposed to direct sunlight, 

 (6) kept in the shade. 



