270 Auxins in Agriculture 



sequently the only successful treatments have involved foliar applica- 

 tions. Maleic hydrazide has so far given the best results (Wittwer and 

 Sharma, 1950). 



Prevention of sprouting of nursery stock of trees and shrubs dur- 

 ing storage has been obtained with the methyl ester of naphthalene- 

 acetic acid applied in a wax emulsion (Marth, 1942). The effects of 

 various auxin concentrations can be seen in figure 113. It is interest- 

 ing to note that at lower storage temperatures the inhibitory effects 

 of this auxin are much reduced and the typical stimulation-inhibition 

 curve for the effects of auxin on bud growth is obtained. These re- 

 sponses are strikingly parallel to the classic type shown in figure 108. 



Naphthaleneacetic acid applied as an emulsion, an ester vapor, 

 a spray and a dip treatment has been tested on several types of tree 

 nursery stock (Ostrom, 1945; Way and Maki, 1946). They found that 

 the growth of buds in storage could be reduced in several different 

 types of tree seedlings if the proper concentration of auxin were used. 

 Effective concentrations varied considerably from species to species. 



0.2 0.4 0.6 0.8 



CONG. OF AUXIN ESTER 



O GMS/IOOO' 



Fig. 113. The effects of brief treatment with the methyl ester of naphthalene- 

 acetic acid on subsequent sprouting of rose bushes in storage at three temperatures 

 (Marth, 1942). 



