20 THE PRODUCTION OF SEEDS 



on the seeds, and invert the jelly glass over them. One advantage of thia 

 germinator is that the progress of germination can be observed from day to 

 day. See also the plan shown at left in Fig. 6. 



For class-room work it is often useful to start one of these germinators 

 each day for a period of 10 days, thus having material ior study in all stages 

 of development. 



Rag Doll Germinators. This germinator is made by using a strip of 

 flannel, about 10 inches wide. Place the seeds on one-half, fold over the 

 other half, then roll and tie loosely. Soak in water for 12 hours, then put 

 in a box or some place where they will remain damp. 



Seeds to Use. Have the pupils bring seeds from home, from the sup- 

 plies that are to be planted on the farm. Vegetable seeds, grass, clover, and 

 cereal seeds of all kinds will serve well. Old seeds as well as new should be 

 used. Seeds from local dealers can also be purchased. When the tests 

 are completed the data should be studied and analyzed to see if it can be 

 determined why some seeds are good and some are poor. 



Comparison of Germinated Seeds. There are several differences in 

 germinated seeds of cereals that few people have observed. For this exercise 

 only good, strong seeds should be used, and special care should be exercised 

 to secure normal, strong germination. 



Germinate seeds of all the cereals, and also peas and red clover. 



When well germinated, study 10 seeds in each case. Record results in 

 tabular form. 



What are the average number of temporary roots in each cereal ? 



State in each case whether the plumule arises from the germ end, 

 middle, or tip of the seed. 



Which germinates quickest, slowest, etc.? 



In a second experiment compare strong seeds with poor seeds, and 

 compare on above points. 



In a third case compare seeds of hard wheat and soft wheat ; hard and 

 soft grains of barley; and kernels from ears of dent corn having hard, 

 flinty kernels with ears having starchy kernels. 



Can you explain why the hardness of a seed should affect the rapidity of 

 germination? Should this be considered in making comparative germina- 

 tion tests with different ears of corn or different varieties of wheat? (See 

 also Chapter XXXV.) 



QUESTIONS 



1. Why do plants store food in seeds? 



2. What other parts are sometimes stored with food? 



3. What part c* nlants do we value most as food? 



4. Name the parts of a seed. 



5. Give the function of each part. 



6. What is the best condition for preserving the vitality of seeds? 



7. How would you define " good seeds " ? 



8. Why is air important in germination? 



9. Do some seeds require warmer temperature for growing? 



10. How long must the young plant live on the seed? 



11. When may large and small seeds be expected to give similar results? 



12. When different results? 



13. How are weak plants eliminated in nature? 



