Scientific Results 



would be from i to 4 parts of the substance in 100,000 parts of 

 water. A small quantity of alcohol may be used for prelimin- 

 ary solution of the substance ; the naphthyl-acetic acids are all 

 but insoluble in pure water. After treatment with the water 

 solution for two to four days the cuttings should be placed 

 in a potting compost. The novice should be warned not 

 to expect to see any extensive root-formation at the end of 

 a few days in the solution; the immediate purpose of the 

 treatment is to enable the cuttings to absorb the growth- 

 substance, which will then initiate root-formation while 

 the cutting is in the compost. The formation of roots, 

 however, usually takes place in appreciably less time than 

 when compost alone is used. 



Figs. 4 and 5 show respectively the effects of solutions 

 of indole-acetic acid (10 parts per 100,000) and a-naphthyl- 

 acetic acid (2 parts per 100,000) on batches of ten cuttings 

 of American holly. These photographs are reproduced 

 by permission from the paper by Hitchcock and Zimmer- 

 man (1936, p. 66). Similar results were obtained with 

 Japanese holly and Taxus cuspidata (Chinese yew) — also 

 difficult plants on which to induce rooting with compost 

 alone. It will be noticed that the cuttings that were almost 

 leafless produced few roots, in agreement with the experience 

 of gardeners who have used compost only. Rooting responses 

 of a number of other species of plants are described in the 

 paper. 



Japanese maple was one of the few species of woody 

 plants which responded consistently to treatment with 

 lanolin preparations, concentrations of from 25 to 100 mg. 

 of indole-propionic acid per gram of lanolin having to be 

 used. As these concentrations are very much higher than 

 those necessary for the solution method, it appears that 

 the lanolin smear method will be less generally applicable 

 than the solution method. Probably lanolin smears will 

 be restricted to treatment of wounds on the parent plant 

 (as after pruning) to hasten the formation of callus, or else 

 as a technique in suitable cases where it is desired to treat a 

 cutting before removal from its parent. Lanolin smears may 



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