Recent Work with Cuttings 



volume. The presence of a small percentage of ethyl alcohol 

 in the treatment solution is not harmful. 



Other solvents have been tried by Tincker (1938). 



Vapours 



Vapours of "synthetics" do not appear to have been tried 

 on cuttings, but see p. 54. 



Additions or Reinforcements to Solutions 



It seems that only one report has been made (Amlong and 

 Naundorf (1938, C) ) of the use of mixed solutions, containing, 

 say, both indole- and naphthyl-acetic acids, and the effects of 

 mixture do not appear to have been very marked, as compared 

 with the effects of either component alone. Hubert et al. (1939 ; 

 bottom of list B) found that a mixture of indole-acetic acid 

 with ascorbic acid gave better results than the single sub- 

 stances. (See p. 68 and 80 for some work with ascorbic acid 

 (vitamin C) alone applied to cuttings), 



Evenari and Konis (1938, D) tried potassium perman- 

 ganate alone and in conjunction with indole-acetic acid in 

 solution, with various results, but the salt alone was not as 

 effective in inducing rooting as was the acid alone. They 

 found that sugar (sucrose ; cane sugar) added to solutions of 

 indole-acetic acid improved the rooting response, and they 

 suggest that the addition of sugar to solutions of growth- 

 substance may have considerable value. 



Other Substances 



The use of permanganate and of sugar as aids to root- 

 formation is not new. A weak water solution of potassium or 

 sodium permanganate is used by practical gardeners as a 

 rooting medium for cuttings of some woody and semi-woody 

 plants. Its rationale is obscure. Some suppose the per- 

 manganate to act by suppressing microbial growth, such as 

 would occur if the cuttings were left long in unchanged 

 plain water. It may conceivably produce growth-substances 

 by oxidation of tissue-material of the cuttings, and it supplies 

 potassium, which some writers overlook. 



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