ABSORPTION OF COPPER FROM THE SOIE BY POTATO 



PLANTS 



By F. C. Cook 



Physiological Chemist, Miscellaneous Division, Insecticide and Fungicide Laboratory, 

 Bureau of Chemistry, United States Departm.ent of Agriculture 



RESULTS OF PREVIOUS INVESTIGATIONS 



Some of the results obtained by a few investigators on the absorption 

 of copper by plants and cells may be summarized as follows : 



Schander^ found that copper in a soluble form is a poison for plant 

 cells of both high and low order. 



Tschirch - believes that living plants are able to absorb copper through 

 their roots and also through the epidermis of the leaves, the amount of 

 copper absorbed being very small, however. 



Haselhoff ^ stated that soluble copper salts are injurious to plants at 

 a concentration of lo mgm. of cupric oxid per liter. When soluble cop- 

 per salts are added to the soil the plant materials, especially the potash 

 and the lime, are dissolved and washed away, as a consequence of which 

 the fertility of the soil is decreased. The action of copper sulphate is 

 more severe on some crops than on others. The presence of calcium car- 

 bonate in the soil prevents or decreases the toxicity of solutions of copper 

 sulphate. 



True and Gies ^ have shown that when lime is used with copper sul- 

 phate solutions the toxicity of the copper is decreased. They state that 

 when there is lime in the soil four times the amount of copper that can be 

 allowed when no lime is found may be present in a soil without exerting 

 a toxic action. 



Forbes ^ found that com grown in soil containing copper held most of 

 the copper in the roots rather than in the tops. He states also that the 

 toxicity of copper depends on the combination in which it exists in the 

 soil, the physical characteristics of the soil, and the chemical composition 

 of the soil, and on climatic and moisture conditions, as well as on the crop 

 grown. 



iScHANDER, Richard, uber die PHYSIOWJCISCHE WIRKTTNG DER KT7PFERV1TR10UCAI.KBRUHE. In 

 Landw. Jakrb., Bd. 33, Heft 4/5, p. 517-584. 1904. 



2 Tschirch, A. das kxtpfer vom standpunkte der gerichtuchen chemie, toxicologie und hy- 

 giene. 138 p., 2 fig. Stuttgart. 1893. Bibliographical footnotes. 



'HaSELHOFF, Emil. UEBER DIB SCHADIGENDB WIREtTNG VON KUPFERSULFAT UND KUPFERNITRAT- 



MALTlGEM WASSER AUF BODEN UND PFLANZEN. In Laudw. Jahrb., Bd. 21, p. 263-276, 2 pi. 1892. 



* True, Rodney H., and GiEs, William J. on the physiologicai, action of some op the heavy 

 METALS IN mixed solutions. In Bvd. Torrey Bot. Club, v. 30, no. 7, p. 390-402. 1903. 



^ FoBLBES, R. H. certain effects under irrigation of copper compounds upon crops. Ariz. Agr. 

 Exp. Sta. Bui. 80, p. 145-238, 16 fig., 4 pi. (i col.). Bibliography, p. 236-238. 



Journal of Agricultural Research, Vol. XXII, No. s 



Washington, D. C. Oct. 29, 1921 



aah Key No. E-17 



(281) 

 65768°— 21 4 



