THE RESPONSE OF PLANTS TO ILLUMINATING GAS 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 227 



Sarah L. Doubt 



(WITH SIX figures) 

 Introduction 



Owing to increasing loss of plants in greenhouses, and of shade 

 trees along city streets, it has seemed worth while to work out 

 simple accurate methods by which gardeners, florists, and forest- 

 ers may detect gas injury. This study falls into two divisions: 

 (1) injury to greenhouse plants due to presence of gas in the air; 

 and (2) injury to trees and bedding plants due to leakage in the soil. 

 It is hoped that as a result of this work any florist or gardener may 

 be able to determine readily the presence of illuminating gas in the 

 air. The presence of gas in the soil as shown by injury to trees is 

 more difficult to determine. 



Considerable work has been done in this laboratory on the 

 effect of illuminating gas and its various constituents upon plants. 

 Crocker and Knight (i) showed that the buds and flowers of 

 carnations are extremely sensitive to traces of illuminating gas 

 in the air. Three days' exposure, 1 part in 40,000, killed young 

 buds and prevented the opening of those which already showed the 

 petals. The flowers were closed by 12 hours' exposure to 1 part 

 in 80,000. One part ethylene to 1,000,000 parts of air prevented 

 opening of the buds, and 1 part in 2,000,000 caused the flowers to 

 close. Their work showed that ethylene is the constituent which 

 is most toxic to plants. Harvey and Rose (6) showed that the 

 relatively high toxicity of ethylene holds for many different species 



of plants. Crocker, Knight, and Rose (2) found etiolated sweet- 

 pea seedlings to be extremely sensitive to gas, and suggest the use 

 of them as test plants for traces of gas. Harvey (8) suggests the 

 use of the castor bean for the same purpose. 



Little is known about the effect of gas on trees. Stone (9) 

 has made a number of observations in the field, which led him to 



209] [Botanical Gazette, vol. 63 



