Plant Qrowth'Suhstances 



The anti-microbial action of potassium permanganate 

 received no support from the work of Curtis (1918), who has 

 contributed the most extensive report of the action of the 

 substance on the rooting of cuttings. His discussion of the 

 role of permanganate may be commended to those interested. 



Curtis also found that cane sugar in simple solution notably- 

 improved rooting of some woody cuttings. A favourable 

 effect of glucose on the rooting of cut etiolated pea shoots has 

 been reported by Amlong (1938, C). Cane sugar, given alone, 

 was found by Evenari and Konis (1938, D) to stimulate callus 

 formation in Bignonia and Myrtus. 



Went (1934, A) used potassium permanganate (0.05 per 

 cent, solution in water) to give "an effective disinfection" to 

 etiolated pea seedhngs from which the roots had been cut off 

 in the course of preparation of the seedlings for a test of 

 "rhizocaline, the root-forming substance". It is clear that 

 Went did not impute to potassium permanganate any positive 

 root-forming activity on such pea seedlings, and he wrote 

 that the salt "decreases the number of roots on the controls". 

 Webster and Robertson (1937) have reported, in a note, that 

 application of potassium permanganate and related salts to 

 some (presumably intact) plants (particularly the cactus 

 Opuntia leucotricha growing in sand) produced a marked 

 growth response (? of the aerial parts), which the authors 

 thought was not solely a manurial effect. No further details 

 have been found. 



Laurie (1928) found the following substances to hasten 

 the appearance of roots on cuttings of the plants named, 

 though they did not increase the ultimate percentage of 

 rooting : 



2 per cent, cane sugar in water: lilac, carnation, heliotrope, 

 climbing Euonymus. 



o-i per cent, potassium permanganate in water: chrysan- 

 themum and the above-mentioned four and some 

 others. 



Vinegar (three teaspoonfuls to a gallon (U.S.) of water) : 

 lilac, Euonymus, chrysanthemum. 



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