PHYSIOLOGICAL PROCESSES IN PLANTS 105 



Questions 



1. How prove that oxygen is liberated in photosynthesis ? 

 (Important.) 



2. Why are the leaves spread out so as to fill in all the in- 

 tervening spaces ? (mosaics.) 



3. The leaves of water plants may differ much in form, de- 

 pending on whether they are above or below water. Explain. 



4. Where is photosynthesis performed in the cactus? 

 Why? 



5. Why are most seed leaves and foliage leaves so different ? 



6. What is the result of the decomposition of carbon dioxide 

 in a leaf ? 



7. Can starch be formed in darkness ? Explain. 



8. Pin the two halves of a cork on the opposite sides of a 

 growing leaf exposed to sunshine. After a day or so dissolve 

 out the chlorophyll, and test with iodine. Explain results. 



9. Can mushrooms manufacture starch ? Explain. 



10. Where is all the starch in the world made ? 



11. Where and how does a plant get its water ? Carbon ? 

 Oxygen ? Hydrogen ? Iron ? Phosphorus ? Nitrogen ? 



12. If cornstalks are burned on the ground, is there as much 

 plant food returned to the soil as when they are plowed under ? 



13. Why does earth whiten celery when banked about it ? 



14. Why do plants near houses often become sickly, and 

 sometimes die ? 



15. If leaves turn yellow and drop off after spraying with 

 oily liquids for killing insects, what has probably happened ? 

 (Remember the functions of the stomata.) 



16. If the stomata of plants are mostly closed at night, when 

 would be the best time to fumigate or spray the plants ? 

 Reasons. 



17. What great danger to plants in the neighborhood of 

 factories, etc. ? Are frequent rains a benefit ? Explain. 



18. Show why the leaves of house plants should receive an 

 occasional washing with water. 



