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The Effect of Aqueous Solutions Upon the Germination of Fungus Spores

1898; University of Chicago Press; Volume: 26; Issue: 6 Linguagem: Inglês

10.1086/327772

1940-1205

F. L. Stevens,

Plant Pathogens and Fungal Diseases

1. Mercuric chlorid is the strongest chemical used in its toxic effect upon the fungi. 2. Potassium cyanid is remarkably weak considering its great toxic action on animals. 3. Various fungi offer different resistance to poisons. 4. The limits of resistance vary in the same species. 5. Alcohol and sodium chloride have a stimulating effect. 6. In general the results are in accord with the theory of hydrolytic dissociation. 7. A chemical may be twice as powerful as another against one fungus, but acting upon another fungus an entirely different ratio may be sustained. 8. The spores of fungi are less susceptible than the roots of seedlings. 9. The Bordeaux mixture holds far more copper than would be needed if it dissociated into simple copper ions. 10. The cathions Hg, H, and Cu are poisonous. 11. The anions CN, CrO4, Cr2O7 and OH are poisonous. 12. The halogen anions are not poisonous. 13. Uromyces offers the greatest range in its susceptibility to poisons. 14. The secondary spores of anthracnoses increase in abundance under the adverse conditions of a toxic solution. 15. Spores protected by actual contact with others may germinate and the tube may grow through a solution which in itself would have prevented the germination of the spore had it been in contact with it. 16. Peculiar knotted or twisted hyphae frequently result from the attempt to grow in a poisonous solution. 17. A spore may be able to germinate and grow slightly in a solution but still be unable to attain full development. 18. Potassium permanganate at certain strengths acts as a selective stain, differentiating uredo- from teleutospores of Uromyces caryophyllinus. 19. Bread may be moistened with a solution which prevents germination of spores. This solution may evaporate and the spores can then grow. 20. An occasional spore may germinate and grow perfectly normally in a solution which prevents hundreds of normal spores around it from germinating. 21. Penicillium in a nutrient medium offers greater resistance to poisons than do any of the other fungi worked upon. 22. Uromyces does not diminish in vigor of growth with the increased strength of the poison, but it does diminish in the percentage of spores which germinate.