Guss GARDEN NA TU RE-STUD Y 249 



Lead children to account for this by finding the stored food. 

 Cut open a bulb and show the layers. 



Compare the thickness and firmness of these in a fresh bulb 

 or in one just beginning to sprout and in one done blooming. 

 For what has some of the stored food been used? 



Fcr Grades j and 4. 

 Starch — One kind of Food Stored by Plants. 



Experim.ent 1. — To show how to detect starch and to find 

 whether it is present in plant storehouses. 



Mix a tiny bit of laundry starch or of cornstarch (such as 

 people use for food) with a little boiHng water in a test-tube. 

 Then add a drop of diluted tincture of iodine. Note the blue 

 color produced. Starch is the only plant material that gives 

 this color with iodine. 



Now treat a bit of each of the following (or as many as possible) 

 with boiHng water (or use portions previously cooked) and then 

 test with iodine: a fresh bulb or one that has new storage parts 

 forming, an onion, a potato, a rootstock, a conn, cabbage, etc. 



Older children may be encouraged to make these tests at home, 

 trying also various grains and other seeds and cereal products. 

 Ask them to report in which they find starch stored. 

 Need for Water — to Dissolve and Carry Starch. — ^Why must 

 bulbs be watered to secure good blooms? Name any kind which 

 needs to be supplied with nothing but water? 



Why then must bulbs have good roots before they produce 

 leaves or flowers? 



Can they get along without light or much heat ? — '■ 



Answer: Yes: until the flower buds are ready to open. Why? 

 (Fuller answers in later lessons). 



For Grade 5 

 Kinds of Plant Storehouses 



Additional Questions for Thought and to Stimulate FvLvther Observa- 

 tion : 

 Where do people usually store vegetables used for food? 



(In cellars or in pits dug in the ground.) 

 Name any plants that store food under ground. Why is that 



a good place? (Protection from injury due to freezing and 



thawing; from injury by animals; etc.; nearness to water supply 



in the spring.) 



