Chemical structure and biological activity 



BIOLOGICAL REACTIONS OF THE ISOMERS 



As we had found in our work on the series of chlorinated phenoxyacetic acids 

 (Leaper and Bishop, 1951) and on the isomeric monochloro orthocresoxy 

 acetic acid (Leaper and Bishop, 1955) that the inhibition of root growth of 

 4-day-old seedlings o^ Lupinus albus served as a good method for differentia- 

 tion of hormone acids, we used the same method here for preliminary 

 biological tests. The results so far have shown that there is not such a wide 

 difference in the inhibitive action of the isomers as there is in the 2-naphthoxy 

 series, the slight increase in inhibition obtained with the (-|-) isomer in this 

 case being parallel to that obtained with the 1-naphthoxy series. However, 

 other important differential specificities are showing up with further bio- 

 logical tests and these will be reported later in a more comprehensive 

 assessment. 



The experimental details of the chemical work described above will also 

 be reported elsewhere. 



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