12 PLANT LIFE 



8. Structure of Leaves. If compound microscopes are available in the 

 school, the students should make cross sections of leaf structures and study 

 the tissues, stomates and guard cells. 



9. Leaves Seek the Light. Have some house plants growing in the window 

 and note the leaves turn toward the sunlight. Turn the plants around half 

 way, and note the length of the time required to change the direction of the 

 leaves toward the light again. 



10. Root Hairs. Plant corn, beans and other large seeds in bottles of 

 sand or soil. Wrap each bottle with black paper, or otherwise shut out the 

 light. After the roots are well formed, remove the covering and study the 

 root hairs and root systems which can be seen through the glass bottles. Of 

 what use is the black paper? 



11. Osmosis Through Egg Membrane. In addition to the exercise sug- 

 gested to show osmosis with a piece of bladder over a funnel tube, try also 

 the exercise describing osmosis with an egg detailed in Productive Farming. 



QUESTIONS 



1. Give the conditions for germination of plants. 



2. How are each of these conditions provided in out-door germination? 



3. Give some cases of difference in depth of planting seeds. 



4. Of what value is the green color in leaves? 



5. What important product is manufactured in leaves exposed to sunlight? 



6. Describe the breathing of plants, and give the leaf structure which pro- 



vides for this. 



7. Give some examples you have observed of the struggle of leaves to get 



sufficient light. 



8. Enumerate the purposes of roots. 



9. Describe the structure and state the use of root hairs. 



10. Define osmosis and state its relation to plant life. 



11. Describe an experiment by which osmotic action is demonstrated. 



12. In what ways do woody plants prepare for winter? How do others pre- 



pare for winter? 



References. U. S. Farmers' Bulletins: 157, "The Propagation of 

 Plants; 586, Collection and Preservation of Plant Material for Use in the 

 Study of Agriculture. 



