Plant Qrowth'Suhstances 



The mainly physiological work of Stoughton and Plant 

 (1938) on sea-kale {Crambe maritima) should be consulted by 

 those interested. 



Warne (1937) has used sprays of indole-acetic and of 

 a-naphthyl-acetic acids in 0-05 per cent, water solution to 

 induce curling of chrysanthemum petals. 



In a study which principally aimed at elucidating some 

 physiological problems, Ferman (1938) suggested that it is 

 not necessary to assume the existence of a hormone newly 

 postulated by Went (1938) under the name caulocaline, 

 and supposed to be a factor in the elongation of stems and 

 lateral buds. Ferman described a number of experiments 

 with solutions and pastes of indole-acetic acid applied to 

 seedlings and cuttings, giving varying results. An aqueous 

 solution of one part in 100,000 applied to the cut surface of a 

 decapitated seedling of Lupinus albus inhibited the develop- 

 ment of axillary buds, but more dilute solutions of that 

 substance rather promoted their development. 



For a report of trials with phenyl-acetic and indole-acetic 

 acids (mostly as sprays) to attempt to bring about the breaking 

 of dormancy of strawberries during the season September- 

 April, see Roodenburg and Tiddens (1938). 



Dihydrofolliculin has been shown to have an action similar 

 to that of hypothetical flowering hormones (florigen, etc.), 

 which may be chemically related to that animal derivative 

 (Chouard (1938) ). Butenandt has also suggested that one 

 sexual hormone may be common to the animal and plant 

 kingdoms. 



The effect of some synthetic growth-substances on the 

 production of new roots on transplanted trees (young red 

 oaks) has been studied by Tilford (1939). Indole-butyric 

 acid was more effective than indole-acetic acid; the cut ends 

 were wrapped in sphagnum moss soaked in the solution, or 

 the roots were soaked in a solution. 



quart of water ; the thousandth-normal solution is still costly. This applica- 

 tion would seem to be one for which a-naphthyl-acetic acid is well adapted, 

 and for which it could be extensively applied if its price comes down to a 

 reasonable figure (see p. 48). 



56 



