Stimulation of Root Growth in Cuttings 79 



in loss of water that the flasks containing them became dry. The twigs 

 in some of the cultures had produced roots. Such cases were noted but 

 no measurements were taken. The twigs from the other hedge (Column 

 A in the table) remained dormant for some time and the buds were just 

 starting at the time when the roots were measured. 



It is shown fairly clearly in table 1 that nutrient solutions of the 

 strengths used in culture work with seedlings are distinctly injurious to 

 woody cuttings. This injurious effect of nutrient solutions, especially 

 at the higher concentrations — 0.1 per cent or above — was further 

 proved by subsequent experiments in which similar results were obtained. 

 In four experiments, sixteen out of a total of twenty cultures showed 

 distinct retardation of growth on the addition of nutrient solutions. 

 Even single nutrient salts, such as CaCU, NaH2P04, KNO3, and KH2PO4, 

 in very dilute solutions, showed marked retardation of the root growth. 

 No very extensive experiments with nutrient solutions were attempted, 

 since the few results obtained' showed clearly that such treatments tend 

 to be .more injurious than beneficial to woody cuttings. A few experiments 

 with herbaceous cuttings indicated that these are less injured by con- 

 centrations up to 0.2 per cent than are woody forms. 



The root development in woody cuttings is usually lessened by an 

 increase in concentration of the nutrient solution, as shown by the figures 

 in table 1. This is somewhat comparable to the effect of high concen- 

 trations of soil or nutrient solutions on seedlings observed by a number of 

 investigators — PoUe (1910), Harris (19i4), Stiles (1915), Brenchley 

 (1916), and many others. The writer has found, however, that woody 

 cuttings are much less tolerant of the stronger concentrations than are 

 seedlings. 



A discussion of the causes for increase or decrease of root growth resulting 

 from a change in concentration of nutrient solutions, and reports of further 

 experiments, are reserved for a later paper. 



INFLUENCE OP TREATMENT WITH POTASSIUM PERMANGANATE 



As already stated, it was found that twigs of Ligustrum ovalifolium 

 developed more extensive roots when treated with potassium permanganate 

 than when treated with a number of other compounds. Potassium 

 permanganate was therefore tried in the first of these experiments. In 



