LEAVES 



153 



134. LEAVES 

 Object. Same as in Experiment 133. 



Apparatus. A vigorous potted plant, cork disks made by mak- 

 ing thin sections of an ordinary bottle cork, and pins. 



Method. Place the cork disks upon leaves so as to 

 cover opposite faces and hold them in place with a pin 

 (Fig. 64). Leave the disks in place 

 for three or four days, then remove 

 them and note the result (Fig. 65). 

 Conclusion. What is the effect 

 of shutting off light from any part 

 of a leaf ? 



Query. Why do gardeners bank 

 up their celery? What is the 

 effect? What other crops are 

 bleached in this way? 



Fold a piece of black felt or 

 thick black paper and punch or cut 

 a hole through both folds. Then 

 lay a leaf between the folds and pin it so that it will remain 

 in position. The leaf will thus be covered with only that 

 portion exposed which is under the hole. 



Set the plant where it will be 

 exposed to strong sunlight and 

 leave it for three or four days. 

 When the covering is removed the 

 leaf will show a green spot where 

 the surface was exposed. All the 

 remainder of the leaf will be pale 

 or almost white (Fig. 66). 

 FIG. 65. Suggestions. Select a plant of 



FIG. 64. 



