THE: PLANT AND THE ATMOSPHERE 43 



flowers. De Saussure 1 found that buds require oxygen by the 

 following experiment. He enclosed woody twigs cut in the spring 

 just before the time for buds to unfold, in jars containing various 

 gases. In hydrogen or nitrogen the twigs decayed, but in the air 



Fig. 8. .Experiment to ascertain the effect of gases 

 on the roots of plants. 



the buds opened and, on analysis of the air, oxygen was found 

 to have disappeared. It thus became evident that the buds require 

 oxygen for their development. 



In similar experiments with flowers, De Saussure found that 

 they consume several times their volume of oxygen in 24 hours. 

 De Saussure 2 tested the effect of different gases upon roots of 



1 Johnson, How Crops Feed, p. 23. 



2 Johnson, How Crops Feed, p. 24. 



