﻿VOLUME XXXV 



NUMBER 2 



Botanical Gazette 



FEBRUARY, 1903 



chemical stimulation and the evolution of 



carbon dioxid. 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY. 



XLIV. 



■ 



Edwin Bingham Copeland. 



(with two figures) 



Several years ago, in a study by Kahlenberg and myself' of 

 the effect of placing small pieces of various chemical elements 

 in water where seedlings were growing, it was found that in a 

 considerable number of instances the roots of the seedlings 

 exhibited an acceleration of grovvthj which we construed as an 

 effect of the chemical employed. In individual cases we found 

 a rapid elongation of the primary root, probably resulting from 

 the action of Bi, Cr, In, Se, Te, Hg, Bo, Pb, W, Co, and Cu. 

 This abnormally rapid growth was frequently followed promptly 

 by death. As the compounds of these elements began to enter 

 into solution, their first action on the plant was that of stimu- 

 lants ; when these same compounds became more concentrated, 

 they became distinctly, often fatally, toxic. 



The stimulating action of minute quantities of various poisons 

 has long been known in the case of a few fungi. Raulin' found 

 that salts of Zn, Fe, and Mn, as well as silicates, caused an 

 unusually luxuriant growth of Aspergillus. Richards^ extended 



'Copeland, E. B., and Kahlenberg, Louis, The influence of the presence of 



pure metals upon plants. Trans. Wise. Academy I2:4S4'474- 1^99- 



^ Raulin, L,:£tudes chimiques sur la vegetation. Ann. Sc Nat. Bot. V. 11 ; 93" 

 299' 1869. 



3 Richards, H. M., Die Beeinflussung des Wachsthums einiger Pilze durch che- 

 mische Reize. Jahrb. Wiss. Bot. 30:665-688. 1897. 



81 



