EXERCISES WITH SEEDS 15 



3. Corn Kernels. — Take a few dry grains of corn and a few that have 

 been soaked in water for a few liours. Hold each grain with the groove 

 towards you and the iK>int or cap downwards. Note that it is covered 

 with a tliin horny coat which can be removed. Within the groove is the 

 young plant or embryo with the root pointing downward. Tlie stem 

 is partly surrounded by a single leaf or cotyledon The entire embryo 

 is surrounded by starch. The remainder of the grain consists primarily 

 of two other forms of starch varying in amount in the ditierent varieties. 

 Cut some of the grains lengthwise and some in cross section, and examine 

 the relationsJiip of the various parts. Make a series of drawings or 

 diagrams to show the preceding {wints. 



4. Write a comparative description of these three types of seeds. 



5. Examine a number of other seeds and group them with some 

 of the above groups or types. 



C. Absorption of Water. — Weigh a small quantity of dry seeds, 

 place in water for a few hours and weigh again. What is the percentage of 

 loss or gain in weight? 



7. Fill a tall bottle or tube with dry seeds and add enough water 

 to cover them. Mark the level of the water at the end of one, two, three, 

 four and five hours respectively. Explain. 



8. Fill a test tube or a bottle or a glass fruit jar with dry beans, tie 

 a strong cloth over the top and immerse in water over night What is the 

 result? Why? 



9. Eemove the seed coats from a quantity of dry beans and weigh 

 without the coats; weigh out an equal amount of dry beans without 

 removing the seed coats. Put the two lots in water for on© hour. Compute 

 changes in weight. Put in water for an additional hour and again com- 

 pute changes in weight Explain. 



10. Take two lots of dry bean» of equal weight. Cover the micropyles 

 of one lot with varnish or sliellae and put both lots in wet sand for two 

 hours. Weigh each lot and compute) changes in weight. Explain. 



11. Germination. — Plant a quantity of corn, beans, peas, melon, 

 squash, cucumber and such other seeds as may be desirable, in clean sand. 

 Remove a few seeds at intervals of three or four days. Make drawings, 

 label the parts and write descriptions and comparisons. (Or, plant the 

 seeds at intervals of three or four days for two or three weeks and then 

 study the seedlings at various stages of growth at the same time. ) 



12'. Cut a small slice off one side of several grains of corn. Ger- 

 minate these with an equal number of uninjured grains between sheets of 

 blotting paper. Is tliere any difference in time of germination? Why? 



1.3. Influence of Moisture, Heat and Light. — (a) Plant two or three 

 kinds of seeds in wet sand in a flower pot and keep in a warm, well-liglited 

 place. 



