SEEDS AND SEEDLINGS. 57 



Two lots of Peas, one of which had been soaked in water at 100 C., 

 the other in water at 15 C., were passed into the vacua at the tops of 

 two parallel tubes of mercury. How would the height of the mercury 

 column be affected in each case ? Would the after addition of caustic 

 potash solution make any difference to the height of the columns ? 



26. Compare the seedlings of Sycamore and Lupin. Note the points 

 of resemblance and difference. 



27. What are the practical difficulties in the way of germinating 

 seeds in an ordinary class-room, and rearing the seedlings for some 

 weeks ? Show how these difficulties can be overcome. 



28. Explain, with drawings, how certain seedlings withdraw their 

 seed-leaves from the seed-coat. 



29. Mention two or three experiments on digestion which can be 

 performed with very simple appliances in an ordinary schoolroom. 

 Give full practical instructions for one such experiment. 



30. Describe the seedlings of three plants in which the cotyledons 

 have entirely different functions. 



31. Describe experiments of a chemical nature by which you could 

 show (a) that starch is changed by the action of your saliva, and (6) 

 that your expired air contains carbonic acid gas. 



32. Name the necessary conditions of germination, and describe ex- 

 periments, which you have seen or performed, to prove what you say. 



33. Describe exactly how you would obtain the dry weight of a 

 seedling. 



What difference would you expect to find between the dry weight 

 of (a) a seed, (&) a seedling of the same plant grown in the dark for 

 some time, (c) a similar seedling grown under normal conditions for 

 the same time ? 



Give reasons for your answer, explaining clearly the source or fate 

 of the materials gained or lost. 



34. Draw (roughly to scale) the young seedlings of any five plants 

 belonging to different natural orders, showing fully the relation of the 

 cotyledons to the rest of the plant, and explain exactly how the food 

 reserve for the seedling is stored in each case. 



