8 MASS. EXPERIMENT STATION BULLETIN 382 



inferior to the solution-immersion method, but other investigators ( 58, 96) 

 have found these methods equally effective if the talc is mechanically- 

 fine enough (49, 58, 114) and if the root-inducing substance is applied at 

 optimum concentrations. More than one concentration of root-inducing 

 substance in the powder is needed to meet the requirements of cuttings 

 of different species (58), so no one dust can be ideal for all (96). 



Powder preparations of indolebutyric acid which had been in open con- 

 tainers, and in continuous use, for a year were no less effective for treat- 

 ment of cuttings (of roses) than were freshly prepared mixtures (62). 



It may develop that one method is better for some species, another for 

 others (34). The powder-dip method improved the rooting of softwood 

 cuttings of Kurume azaleas, although they were injured by treatment for 

 24 hours with a very dilute solution of indolebutyric acid (57). The 

 powder-dip method gave satisfactory results with cuttings of a number 

 of species of ericaceous plants but was better than the solution treatment 

 only with male-berry, the cuttings of which rooted very poorly after 

 solution treatment (90). Cuttings of Lantana and Poinsettia are also 

 subject to injury when soaked (18), and the powder-dip rnethod or the 

 concentrated solution-dip method (see below) is better for such species. 



Immersion of basal ends of cuttings in water for 24 hours, previous to 

 their insertion in sand or sand-peat, interfered with the rooting of cuttings 

 uf Norway spruce (24), Chinese wistaria, Syringa Prestonae, Jasminum stcph- 

 anense, two species of Magnolia, and some other species (18, 125) and had 

 a bad effect on the rooting of leaf-bud cuttings of a raspberry (2). 



Not all species react in this way, the cuttings of some being benefited 

 rather than injured by immersion of their basal ends in water for at least 

 a few hours. Softwood cuttings of buttonbush, sweet gale, osage-orange, 

 Ceanothus Delilianus. Viburnum tomentosum, Fothergilla Gardeni, Hydrangea 

 quercifolia, and H. macrophylla treated for 24 hours with water rooted in larger 

 percentages than did cuttings directly inserted in the rooting medium (87). 

 November cuttings of Taxus media var. Hicksii, the basal ends of which had 

 stood in water for six weeks before their insertion in sand-peat, rooted 

 100 percent, as did untreated cuttings, but the best roots developed on 

 the cuttings which had been in water. 



It should be noted in this connection that some investigators (16, 47, 

 117, 119) have treated control cuttings, checks, with water for the same 

 number of hours that other cuttings were immersed in a solution of growth 

 substance; but in the work done here, control cuttings were directly in- 

 serted in rooting media without any previous treatment with water for, 

 in practice, cuttings are either treated with a growth substance or not at 

 all. 



Concentrated Solution-dip Method of Treatment 



Treatment of cuttings by this method consists in merely dipping the 

 basal half inch of cuttings in a concentrated solution containing 1 to 20 

 mg. root-inducing substance in 1 cc. of water or mixture of water and 

 alcohol (49). Like the powder-dip method this reduces the time of treat- 

 ment to a few seconds and is said to be about as effective at optimum 

 concentration as the standard or solution-immersion method (49). The 

 last named is, of course, a matter not of seconds but of hours and this 

 is a point of some importance with cuttings of species which may be 

 injured by a prolonged soaking in a solution or even in water. 



