CATALASE, HYDROGEN-ION CONCENTRATION, AND 
GROWTH IN THE POTATO WART DISEASE 
By Freeman Weiss, Pathologist, Office of Cotton, Truck, and Forage Crop Disease 
Investigations , and R. B. Harvey , formerly Physiologist, Office of Plant Physiologi¬ 
cal and Fermentation Investigations, Bureau of Plant Industry, United States Depart¬ 
ment of Agriculture 
An attempt was made by one of the authors 1 to determine the rela¬ 
tive importance of the physiological factors of the hydrogen-ion con¬ 
centration, catalase, oxidase activity, and osmotic concentrations which 
are correlated with growth. Determinations were made upon tissues in 
which overgrowth was induced by inoculation with Bacterium tumeja- 
ciens Sm. and T. and as a result of injury from freezing. 2 In both of 
these cases the production of overgrowth was attended by aii increase 
in catalase activity and decrease in hydrogen-ion concentration. It was 
shown to be improbable that overgrowths in tissues infected with Bad. 
tumefaciens were produced by differences in osmotic concentration 
brought about by the organism, since no considerable difference in 
osmotic concentration between diseased and healthy tissue could be 
found. In the mosaic disease of tobacco, in which a decreased growth 
is shown in the palisade cells of the diseased areas, there was a corre¬ 
sponding decrease in catalase accompanied by increased hydrogen-ion 
concentration of the expressed juice. 3 These cases would lead one to 
believe that increase or decrease in hydrogen-ion concentration brought 
about inverse changes in catalase, since it is known that catalase dete¬ 
riorates rapidly in acid solutions and remains constant at acidities between 
P h 7 and P H 8. Boas 4 reports that the acidity of the cell sap of potatoes 
affected by leafroll is less than that of healthy plants; but whereas dis¬ 
eased plants show an increase in catalase content in some cases, this 
relation did not hold generally. 
An idea of the importance of the factors correlated with the produc¬ 
tion of overgrowths can be obtained only by a study of conditions attend¬ 
ing their production by various means or by different types of organisms. 
Excellent material for this work, in which there is a marked growth 
response on infection of the tissue, was found in the wart disease of the 
potato (Solarium tuberosum L.) casued by Chrysophlydis endobioiica 
Schilb. These overgrowths are very striking in appearance and size, 
1 Harvey, R. B. relation of catalase, oxidase, and ii+ concentration to the formation of 
overgrowths. In Amer. Jour. Bot., v. 7, no. 5, p. 211-213. 1920. 
2 - hardening process in plants and developments from frost injury. In Jour. Agr. 
Research, v. 15, no. 2, p. 83-112, 3 fig., pi. 7-11 and A (col.). 1918. literature cited, p. 108-m. 
3 -HYDROGEN ION CHANGES IN THE MOSAIC DISEASE OF TOBACCO PLANTS AND THEIR RELATION 
To catalase. In Jour. Biol. Chem., v. 42, no. 3, p. 397-400. 1920. 
4 Boas, Friedrich, beitrage zur kenntnis des kartoFFELABbauES. In Ztschr. Pflanzenkrank., Bd. 
29, Heft 5/6, p. 171-176. 1919. Bitcraturverzeichnis, p. 176. 
Journal of Agricultural Research, 
Washington, D. C. 
yp 
Vol. XXI, No. 8 
July 15, 1921 
Key No. G-237 
(S89) 
