214 



GROWTH OF PLANTS 



on a large number of species. The basal end of the cutting is dipped directly 

 into the alcohoUc solution and planted immediately in the rooting medium. • 

 Similarly, a soluble salt of a-naphthaleneacetic acid may be used in water 

 instead of alcohol (Fig. 78B). This is a simple method since it does not 

 require preliminary soaking before planting. 



Figure 79. The powder dip method for propagating cuttings with growth substances 

 illustrated with Camellia species. A, Moist Camellia stems dipped into powder prepara- 

 tions containing 10 mg of /3-indolebutyric acid per g of talcum powder. B, Left: control 

 treated with pure talcum powder; right: rooted cuttings which had been treated with 

 talcum powder preparation containing 10 mg of /3-indolebutyric acid per g of talc. 



The third and the most extensively used method at the present time is 

 the powder dip method (Fig. 79). This involves a mixture of 1 to 10 mg 

 of /3-mdolebutyric acid, a-naphthaleneacetic acid, or other substances per 



