2. Explain how it is that a green plant cannot carry on its nutrition in darkness.(1892)
3. What part of its food does a green plant obtain from the air? In what form, and under what conditions, is it taken in? (1889)
4. Describe the method of water cultures, and give the general results of a set of experiments. (1898)
5. Give experimental proof that green plants require to be fed with combined nitrogen. (1897)
6. What are the necessary conditions for the formation of starch in a plant? Mention experiments which support your statements. (1896)
7. Explain the influence of light on a growing plant. Illustrate your answer by reference to the changes in a ripening and germinating bean. (King’s Schol. 1903)
8. How can it be proved experimentally that a green plant draws some, but not the whole, of its nourishment from the air? (1904)
Fig. 22.—Two mustard seedlings of equal age.
E, grown in the dark;
N, grown in ordinary daylight.