CHAPTER XVII 



Miscellaneous Uses of Auxins 



Several of the minor uses of auxins relate to fruit growth and develop- 

 ment and of these perhaps the most promising are the uses of auxins 

 to increase fruit size and induce early maturation and coloration. 



ALTERING FRUIT SIZE AND MATURATION 



The first report that avixins could increase fruit size was made by 

 Clark and Kerns (1943). These workers found that the application of 

 naphthaleneacetic acid to growing pineapple fruits could increase the 

 final size of the fruits as much as ten or twenty per cent. Some of 

 their data are shown in figure 121, from which it can be seen that 



< 



1000 MG/L 



CONC. OF AUXIN 



Fig. 121. The effect of auxin (naphthaleneacetic acid) applied during fruit growth 

 upon the ultimate size of pineapples (Clark and Kerns, 1943). 



concentrations of 100 and 500 nig./l. resulted in appreciable gains in 

 fruit weight. Similar gains in fruit size have been reported for limes 

 (Erickson and Brannaman, 1950), seedless grapes (Weaver and Wil- 

 liams, 1950), apricots (Crane and Brooks, 1952), strawberries (Zielin- 

 ski and Garren, 1952), and possibly the fig (Crane and Blondeau, 

 1949). The procedure for pineapples has been worked out in detail 

 294 



