Stimulation of Root Geowth in Cuttings 



117 



period, which resulted in rapid growth of tops when the twigs were placed 

 in the cutting bench. This resulted in no injury to the quick-rooting 

 Ligustrum cuttings, but many slow-rooting forms would fail to root 

 under such conditions. If immature cuttings could be taken early in the 

 autumn and caused to root as well as mature cuttings taken later, they 

 would have a longer time in which to become well rooted before winter 

 and before the end of the rest period. 



Figures given by Dachnowski (1914) showing results when tomato 

 cuttings were placed in a large variety of solutions, indicate that the addi- 

 tion of glycocoll markedly increases root growth and that cane sugar has 

 a somewhat similar effect. 



Knudson (1916) found that an increase in sugar content of the nutrient 

 solution very markedly increases root growth in various seedlings when 

 grown under sterile conditions. The top growth also is benefited, but 

 the roots respond especially well to an increased supply of carbohydrates. 



EFFECT OF LIMITED TREATMENT WITH SUGAR SOLUTIONS ON IMMATURE TWIGS 



Treatment with different concentrations 



On August 30 cuttings were taken from large succulent leaders on 

 Ligustrum bushes. Six leaves were left on each twig, and there were 

 four twigs in a culture. The twigs were placed for three days in the solu- 

 tions indi<?ated in table 12, after which the leaves were removed and the 

 twigs were rinsed and placed in distilled water. 



TABLE 12. Effect of Sugar Solutions o:j Immatube Twiqs 

 (Duration of. experiment, August 30 to October 15, 1915) 



Solution 



Average length of roots per twig 

 (in millimeters) 



Cul- 

 ture 1 



Cul- 

 ture 2 



Average 



Relative 

 to check 



as unity , 



Check — Distilled water 

 Cane sugar, 1 per cent . . 

 Cane sugar, 5 per cent . . 

 Cane sugar, 10 per cent. 



4 

 20 

 35 

 58 



4 

 15 

 19 

 81 



4± 1.5 

 17. 5± 3.3 

 27. 0± 7.4 

 69.5±16.3 



1.00±0,38 



4.37±0.82 



6.75±1.85 



17.37±4.08 



