20 MASS. EXPERIMENT STATION BULLETIN 427 



recommended by the manufacturer for rooting carnation cuttings. Spores in 

 drops of these hormone solutions were also placed on glass slides and incubated 

 in moist Petri dishes. The following hormonized powders were used: 



Rootone (Old T^'pe) American Chemical Paint Company 



Rootone (New Type) American Chemical Paint Company 



Hormodin No. 1 Pojvder.. Merck and Company 



Root-Gro Root-Gro Chemical Company 



Thiourea 1-2,500 in Talc 



The following quantities of hormonized solutions were used in J^ pint of water: 



Hormodin A - -.. 0.6 cc Merck and Company 



Root.-Gro Concentrate 12.5 cc Root-Gro Chemical Company 



Auxilin _ 0.6 cc Pennsylvania Chemical Corporation 



No toxicity to the spores was revealed. Spore germination appeared to be 

 accelerated by all, irrespective of the active ingredient peculiar to each brand. 

 The powders or solutions could not be considered fungicidal and no claims to that 

 effect are made by the manufacturers. 



The idea of treating carnation cuttings with hormone powders and solutions 

 was introduced at a time when carnation growers had already adopted the 

 practice of soaking the cuttings in potassium permanganate solution before 

 planting them in sand. Thus the two practices appeared to conflict. It is re- 

 ported that potassium permanganate inactivates the hormone substance and 

 that when both are used the root-inducing substance should be applied last (22, 

 23). 



Kirby (36, 37) reported the least percentage of diseased cuttings due to Alter- 

 naria, the greatest fresh weight, and the best rooting from immersing the cuttings 

 in potassium permanganate solution, then washing them, and subsequently 

 dipping the cut ends in a hormone dust. He found that when the cut ends of 

 carnation cuttings were dipped in naphthalene acetic acid dust, 17 percent of the 

 cuttings showed Alternaria branch rot in contrast to 26 percent of those im- 

 mersed for 10 minutes in a 1-1,000 solution of potassium permanganate and 60.5 

 percent of those not treated. When the cuttings were immersed 10 minutes in 

 potassium permanganate solution, washed, and the cut ends then dipped in 

 naphthalene acetic acid dust, the percentage of diseased cuttings was reduced to 

 5 percent. Since the brands of hormone materials studied are not fungicidal to 

 spores of the organisms pathogenic to carnations, the control reported by Kirby 

 (36, 37) is obviously not due to the action of the dust upon the spores of the 

 Alternaria pathogene. Experimental trials repeating the procedure and mate- 

 rials employed by Kirby gave nothing significant in favor of supplementing 

 potassium permanganate with a hormone chemical (Fig. 8). 



Cuttings from Ivory in February were used in another test. The cuttings 

 were grown in sand for 19 days and rooting was classified into groups as good, 

 poor, and not rooted. In a second test King Cardinal, Pelargonium, Wivelsfield 

 Crimson, and Woburn were used and the results were recorded on March 7; 22 

 days after the cuttings were planted in the sand (Table 12). 



Many tests have revealed the virtue of potassium permanganate in accelerating 

 rooting and improving the growth of carnation cuttings in the propagating 

 bench. The value of hormone substances for this purpose is recognized (38,46). 

 Either treatment is superior to none for promoting growth of roots. Nevertheless, 

 most growers do not regard the hormone materials with favor except for varieties 

 like Pelargonium that are hard to root, and prefer to root their cuttings in the 

 natural way. Injury from the use of hormone materials has occurred frequently. 



