RESISTANCE OF PLANTS 387 



wise, varieties rich in certain vitamins are usually readily infected 

 by parasites, which do not have the capacity to elaborate them 

 though they are indispensable for their growth (Suchorukov). 

 Infection is stimulated by activity of the oxidation processes, 

 and it is sometimes possible to establish a parallelism between 

 infection and the activity of peroxidase and other oxidation 

 enzymes (Richter). 



A detailed discussion of the phenomenon of resistance to 

 fungal, bacterial, virus, and other infectious diseases lies beyond 

 the scope of a course in plant physiology. 



General References 

 1. Soil Moisture and Growth 



Aamodt, O. S. a machine for testing the resistance of plants to injury by 



atmospheric drought. Can. Jour. Res., 12: 788-795, 1935. 

 and W. H. Johnston. Studies on drought resistance in spring 



wheat. Can. Jour. Res. {Bot. Sci.), 14: 122-152, 1936. 

 Beck, W. A. Osmotic pressure, osmotic value, and suction tension. Plant 



Physiol, 3: 413-440, 1928. 

 . Determining the osmotic value at incipient plasmolysis. Trans. 



Am. Micros. Soc, 48: 204-208, 1929. 

 . Variations in the Og of plant tissues. Plant Physiol., 6: 315-323, 



1931. 

 Breazeale, J. F. Maintenance of moisture-equilibrium and nutrition of 



plants at and below the wilting percentage. Ariz. Agr. Expt. Sta. 



Tech. Bull. 29, 1930. 

 Calvert, J. Drought resistance in wheat. The "bound" and "free" 



water of expressed sap from wheat leaves in relation to time and soil 



moisture. Protoplasma, 24: 505-524, 1935. 

 Campalungan, a. v., and H. F. Murphy. Wilting coefficient studies. 



Jour. Am. Soc. Agron., 22: 842-847, 1930. 

 CoLLisoN, A. C. Lysimeter investigations, IV. Water movement, soil 



temperatures, and root activity under apple trees. A^. Y. State Agr. 



Exp. Sta. Bull. 237, 3-31, 1935. 

 Conrad, J. P., and F. J. Veihmeyer. Root development and soil moisture. 



Calif. Agr. Exp. Sta. Hilgardia, 4: 113-134, 1929. 

 CuLLiNAN, F. P., and J. H. Weinberger. Studies on the influence of soil 



moisture on growth of fruit and stomatal behavior of Elberta peaches. 



Proc. Am. Soc. Hort. Sci., 29 (1932): 28-33, 1933. 

 Curtis, O. F., and H. T. Scofield. A comparison of osmotic concentra- 

 tions of supplying and receiving tissues and its bearing on the Miinch 



hypothesis of the translocation mechanism. Am. Jour. Botany, 20: 



502-512, 1933. 

 Dastur, R. H., and E. Bapista. Osmotic and suction pressures of the 



rice plant (Oryza sativa L.) Indian Jour. Agr. Sci., 1: 166-188, 1931. 



