56 SEEDS AND SEEDLINGS. 



14. How are the reserve food-substances present in a seed made 

 available for the nourishment of the young plant ? 



15. What is meant by digestion ? How are starch, proteids, and oils 

 digested? To what extent are the processes of digestion similar in 

 plants and animals ? 



16. How could you measure roughly the work done by a seedling 

 in emerging from the soil? Where does the necessary energy come 

 from? 



17. What is the usual appearance of the top of the shoot of a young 

 seedling, and what is the advantage of this? How do seedlings of 

 Maize and Wheat differ from most other seedlings in this respect, and 

 how do they emerge from the soil ? 



18. What is the difference in structure between endospermic ( " albu- 

 minous") and non-endospermic ("ex-albuminous") seeds? Show that 

 both kinds of seeds may contain the same kinds of food, and explain 

 why the old terms "albuminous" and "ex-albuminous" often lead 

 students into wrong ideas about seeds. 



19. Describe, with sketches, the seed, the mode of germination, and 

 the seedling of the following plants : Pea, Kidney Bean or Scarlet 

 Runner, Oak, Ash, Wheat, Maize, Cress, Linseed, Sycamore, Onion, 

 Cucumber or Gourd or Vegetable Marrow, Sunflower, Date, Pine, 

 Horse Chestnut, Castor Oil plant, Mustard. 



20. Write an essay on the uses, and the behaviour during germina- 

 tion, of the cotyledons in the various seeds whose germination you 

 have watched. 



21. Enumerate the chief reserve materials of food which are stored 

 in the seeds of plants. Give an example of each, and explain how the 

 embryo or seedling is enabled to utilise the food. 



22. Explain why it is that certain seeds for example, Peas and 

 Beans split readily when the testa is removed. Name as many other 

 such seeds as you can, and describe in some detail the germination of 

 any one of them. 



23. Suppose you had two flourishing seedlings of the same size, and 

 you grew one in the dark and the other in the light. How would each 

 differ from its original weight in the course of a few weeks ? If one 

 of them had gained considerably, how would you demonstrate exactly 

 to what the increased weight was due ? What other differences would 

 you notice between them ? 



24. What are the chief points you would emphasise in a lesson on 

 the germination of seeds ? What material would you select for the 

 practical work of the class ? 



25. What is respiration, and how is it affected (a) by heat, (6) by 

 light, (c) by increased rapidity of growth ? 



