Recent Work with Cuttings 



Traub (1938) (of Orlando, Florida) has reported tests of 

 over a hundred chemicals on the rooting of sub-tropical 

 plants. Most of the reagents he tried are not usually regarded 

 as growth-substances, and many of those he used have not 

 been tested by other workers. A number of substances that 

 gave some improvement of rooting (over controls) of Passi- 

 flora quadrangularis or Bignonia venusta are listed in his paper ; 

 most of them were inferior to indole-butyric acid in 002 

 per cent, aqueous solution, even in qualitative tests. Salicyl- 

 idene acetamide (quarter-saturated solution), and tetra- 

 furfuryl alcohol and sodium naphthyl-4-sulphonate (both in 

 o-oi per cent, solution) were found to have an approximately 

 equal efficacy with indole-butyric acid within the scope of 

 these rough tests. Amongst substances of the more customary 

 class, phenyl-acetic acid, diphenyl-acetic acid, indole-3-«- 

 propionic acid, and ascorbic acid, were tried; they were less 

 useful than the indole-acetic, indole-butyric, and a-naphthyl- 

 acetic acids, but it is not clear whether they were found by 

 Traub to have any value at all. 



Many plants (listed in the paper) were considered from the 

 standpoint of their suitability as test objects, and the out- 

 standing ones for sub -tropical use were found to be Passiflora 

 species, especially P. quadrangularis and P. ligularis. Cuttings 

 of the former can be used in the upright or inverted positions. 

 Inversion has the advantage that the controls root late and 

 sparely. Cuttings were made with the major portion of one 

 internode and one node with leaf attached. 



Though reported in 1938, this work was begun in 1933, that 

 is, prior to the identification of heteroauxin as indole-acetic 

 acid. In another paper Traub and Marshall (1937) briefly 

 reported on the rooting of papaya cuttings {Carica papaya) ; 

 they have worked with three Carica species. 



Gillett and Jackson (1937) and other workers have obtained 

 encouraging results with rooting of cuttings of Cojfea arahica 

 treated with 10 parts of indole-acetic acid per 100,000 of 

 water, and with appropriate dilutions of a commercial 

 preparation. 



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