Synthetic Qrowth'Suhstances in Qrafting 



Possible Non- Biological Applications 



Robbins and Jackson (1937) have recorded an effect of 

 indole-acetic acid on elongation of dead stem-wall material 

 (cotton thread and hemp cord). These textiles stretched more, 

 under the influence of a weight, when treated with lanolin 

 containing 0-2 per cent, of indole-acetic acid, than when 

 treated with lanolin alone. Stewart (1938) attempted to 

 repeat this work and also extended its scope. He found no 

 conclusive evidence of an effect of indole-acetic acid on the 

 extensibility of living or dead stem- and root- cell-walls. 

 Artificial silk (called by him "regenerated cellulose"), however, 

 was found by Stewart to have an increased extensibility in 

 dilute solutions of certain organic acids, such as acetic and 

 oxalic, which he says are "known not to be growth-sub- 

 stances",^ as well as in 0*2 per cent, aqueous indole-acetic acid. 



'At the Chelsea Flower Show of 1939 an unknown interlocutor told the 

 author that several years ago he had obtained excellent rooting of Bougain- 

 villea cuttings in India by treating them with dilute formic acid ; untreated 

 cuttings failed almost wholly to root. It is not known to the author how this 

 substance was introduced into use for that purpose ; it may represent an echo 

 of some work by H. E. and E. F. Armstrong {Annals Bot. (191 1), 25, 507; 

 Proc. Roy. Soc. Lond. B, (1910), 82, 588), who examined some effects of 

 dilute acids on leaves, but did not report root-formation, or apply the 

 substances to cuttings. 



REFERENCES D 



Amlong, H. v., and Naundorf, G. (1938). Gartenbauwiss., 



12, 116 {homHort.Abs.) 

 Bennett, J. P., and Skoog, Folke (1938). Plant Physiol., 13, 



219. 

 Chailakhian, M. H. (1937). Bull. Acad. Set. U.R.S.S., 198 



(after Hort. Abs. 1939, 9). 

 Chailakhian, M. H., and Zhdanova, L. R. (1938). Compt. 



rend. Acad. Sci. U.R.S.S., 19, 303 {irom Hort. Abs.). 

 Chouard, P. (1938). Chron. Bot., 4, 13. 

 Chouard, P. (1939). Les "Hormones" de croissance et leur 



emploi pratique, specialement dans le bouturage. Rev. 



bot. appl. Agric. trop., 19, 332-350. 



57 



