CHAPTER 5 



Effect of Certain Lethal Gases upon 

 Plants and Animals 



The study of the effect of physiologically active gases upon plants led a 

 group of investigators at the University of Chicago and later a group of 

 research workers at Boyce Thompson Institute to investigate the effect of 

 other gases upon plants and animals. 



Injury to Trees and Shrubs from Leaks of Artificial 



Illuminating Gas 



When we discuss illuminating gas injury to trees and shrubs along streets 

 or in parks, there are three factors that must be considered that are not 

 involved in gas injuries in greenhouses: (1) soluble constituents of the gas 

 will accumulate in the soil about the roots in the first case, whereas they 

 will be absorbed by the soil and not reach the air of the greenhouse in the 

 second; (2) the roots as well as, or even more than, the tops of the plants 

 must be considered in tree and shrub injury; and finally, (3) there is a 

 free movement of air outside, that will take the gases away from the tops 

 of the plants instead of holding them about the plants, as is the case in the 

 greenhouse. 



Harvey and Rose ^^ found that when root systems of plants were sealed 

 in the soil and subjected to moderate concentrations of Chicago artificial 

 illuminating gas various abnormal growths occurred. These responses were 

 the same as those occurring when ethylene was added to the soil in amounts 

 equal to that in the gas. The following groA\i:h changes occurred in one or 

 another of the several kinds of plants treated: coiling or swollen growth 

 near the tip of roots, proliferation of cortical cells on the upper part of roots 

 and lower parts of stems, and fall of leaves. In the last case the ethylene 

 was absorbed by the roots and passed up through the stem to induce leaf 

 fall. In high concentrations of illuminating gas the roots were killed and 

 the whole plant died. Harvey and Rose also flowed illuminating gas 

 through soil bearing plants, very slowly in some cases, and very rapidly in 

 others. In the former they observed ethylene-induced growth responses 

 and in the latter death soon occurred, which they attributed in part to 

 the lack of oxygen, though admitting that toxic substances in the gas may 

 have played a part. They observed that with slow flow of gas, all the starch 

 disappears from the cortex of the roots, and believe that this, together with 

 the proliferation of tissue on roots and lower parts of the stems, may serve 



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