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TORREYA 



Though in the same family group, tomato and potato tissues do not respond 

 alike to a given substance, due, perhaps to the difference in their genetic consti- 

 tution. Apple and lilac stem cuttings can be induced through chemical treatment 

 to produce adventitious roots in the spring of the year but not in autumn or 

 winter. Though the tissue is receptive at an early age, the capacity to respond 

 to the chemicals is soon lost. 



B 



Fig. 4. Shoots and leaves showing formative influence of growth substances. A. Datura 

 stramonium: left, control; middle, sprayed with a solution of 2,4-dibromophenoxyacetic 

 acid (50 mg./l.) ; right, sprayed with a solution of ^-aminophenoxyacetic acid (500 mg./l.). 

 B. Cucumber (Cuciimis sativiis) leaves: left, control leaf; right, 4 leaves taken from one 

 plant after the terminal bud had been sprayed with a solution of ^-naphthoxyaqetic acid 

 (100 mg./l.). 



1 



