A laboratory course is plant physiology, especially as a basis for ecology

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1901 Excerpt: ... 13. This maybe tested by comparing the growth of seedlings in water containing minerals, with the growth of those in water lacking them. Prepare two germinators as follows: Take two common tumblers with sloping sides, and make rings of wire or glass tubing of such a size that they may be supported by wire or tubing inside and about half-way up the tumblers. Sew tightly over these rings pieces of cheese-cloth which hang to the bottom of the tumblers. Fill one to near the ring with distilled water, and another to the same height with nutrient solution. Sow about twenty radish or mustard seeds on each cloth, and observe the comparative rate of growth. Place black paper around the bottoms of the tumblers to keep the roots in their natural darkness and to prevent the development of Algae in the nutrient solution (see Fig. 13). (Cheese-cloth sometimes does not absorb water readily, in which case it may be helped by thorough boiling; or instead of it, thin sheets of cotton batting may be used to advantage.) A better method of supporting the cheese-cloth is to cut the inside from corks, making floating rings a little smaller than the diameter of the tumbler; or, still better are rings of an inch in depth turned from pine on a lathe. The nutrient solution is to be made up from one of the formula; commonly given in physiological works, as for instance Detmer, 2, 3; Goodale, 251. It is best to make up a stock for use of the class, but it should be made freshly each year. A more direct proof that a mineral salt maybe absorbed in solution through roots would probably be found by growing seedlings in a dilute solution of lithium citrate, and subsequently testing with the spectroscope the bands given by holding sections of the tissue in the bunsen flame. But perhaps such...