108 



Fundamentals of Auxin Action 



pold and Guernsey (1953) who have demonstrated that various carbo- 

 hydrates, amino acids, and organic acids applied to pea seedlings in 

 minute amounts could quantitatively inhibit flower formation, and 

 application of auxins would in the same manner quantitatively inhibit 

 flower formation. The criterion of flowering, or earliness, was taken 



UJ 

 O 



o 



13 



^ 



• >^ Arginine Plus 

 ^>^ Auxin 



f 



10 



-8 



10- 



10 



-6 



10-^ M. 



CONG. OF ARGININE 



Fig. 49. The inhibition of flowering in the pea by arginine and the reversal of 

 its effect by the addition of auxin, 0.01 mg./l. naphthaleneacetic acid (Leopold and 

 Guernsey, unpublished). 



to be the node of first flower. However, as figure 49 indicates, the 

 inhibitory action of the carbohydrates, amino acids, or organic acids, 

 could be erased by the concomitant addition of auxin. 



The interesting subject of the influence of auxins on flowering is 

 discussed in more detail in chapter XIV. 



FRUIT DEVELOPMENT 



The classic researches of Gustafson (1936 et seq.) have established 

 that auxins are capable of causing the commencement of fruit develop- 

 ment in many species without pollination. Indeed it appears that the 



