Plant Qroivth'Suhstances 



Non- Woody Plants 



Demonstration experiments with some non-woody plants 

 have already been mentioned; these were performed to test 

 the efficacy of the then new synthetic growth-substances 

 rather than for purposes of propagation. Recently Nowosad 

 (1939) has described some preliminary tests with indole- and 

 a-naphthyl-acetic acids in the rooting of cuttings of some 

 forage plants, and has concluded that the synthetics may be of 

 value to the plant breeder. It may be recalled that the 

 planting of alfalfa (lucerne) on the field scale from cuttings 

 was practised experimentally in England in the eighteenth 

 century. 



The optimal treatments for alfalfa and clover were : (i ) 

 50 parts per million in talc, applied to the fresh scar of 

 cuttings; (2) dipping basal ends 12 hours in 5-50 p. p.m. 

 solution; (3) feeding 10 p. p.m. dissolved in nutrient culture 

 solution. 



No satisfactory rooting of timothy {Phleum pratense) was 

 obtained. It is pointed out that the degree of success with 

 plants reacting positively is influenced by such factors as 

 temperature, humidity, and light, in the greenhouse ; degree of 

 maturity of cuttings; pH and chemical composition of the 

 medium in which the cuttings are planted — as well as by the 

 kind of growth-substance chosen. 



See also the work with kudzu {Pueraria hirsuta) men- 

 tioned on p. 45. 



Substances 

 Solvents 



As already mentioned, the potassium and sodium salts of 

 indole-acetic acid and related acids are sufficiently soluble 

 in water. Such salts, particularly the potassium salt, have been 

 used and recommended by a few workers. Most of the alkali 

 salts are not generally available. 



The usual practice with the indole- and naphthyl-acetic 

 acids as growth-substances is to rub them up with a little 

 ethyl alcohol, in which they dissolve fairly readily, and 

 to dilute that alcoholic solution with water to the desired 



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