On form and function of plant growth substances 



Figure 6. Pea test. 



(a) XII : 1000. 750. 500.1 Q-^ mo///. (b) XIII : 1000. 750. 500.10~3 wo///. 



(c) XIV: 1500. 1000. 750. 500.10-5 mo///. (d) XV : 1500. 1000, 750. 500.1 0"^ mo///. 



(e) XVI : 1500, 1250, 1000, 750. 10"^ mo///. ( /) XVII: 1500. 1250. 1000, 750. 10-^ mo///. 



a-SUBSTITUTED PHENYLACETIC ACIDS 



The effect of a-alkyl-substituents in phenylacetic acid has been discussed up 

 to three-carbon substituents (Veldstra and Aberg, 1953). This series was 

 extended by investigating the (DL)/2-butyl-, tert. -butyl-, and «-amvl-derivatives 

 (XVIII) 



COOH 



HC 



R 



— CrI.2CH2CH2CHjj 



R = < -C(CH3)3 



. — CH2CH.2CH.2CH2CH3 



XVIII 



125 



