SELECTED BIBLIOGRAPHY 479 



of the cytoplasm. The epithelial cells also swell to several times their original 

 volume during the first few days of germination. 



Not long after these changes occur in the appearance of the cells of the 

 epithelium the cell walls of the endosperm cells adjacent to the epithelial 

 layer begin to disappear, and the starch grains in the cells of the endosperm 

 begin to show corrosion. Shortly afterwards transitory starch grains appear 

 in the parenchymatous cells of the scutellum. Enzymes produced in the 

 layer of epithelial cells apparently have diffused into the endosperm and 

 there set in operation digestive processes, the products of which subsequently 

 diffuse into the scutellum. This seems to be the mechanism whereby the 

 embryo obtains food from the endosperm during the process of germination. 

 The principal enzymes secreted by the embryo are hemicellulase which results 

 in the dissolution of the endosperm cell walls, and diastase (amylase plus 

 maltase) which results in the digestion of starch. Similar phenomena un- 

 doubtedly occur during the germination of other kinds of seeds. 



Suggestions for Collateral Reading 



Haldane, J. B. S. Enzymes. Longmans, Green and Co. London. 1930. 

 JMiller, E. C. Plant physiology. 2nd Ed. JVIcGraw-Hill Book Co. New 



York. 1938. 

 Waksman, S. A., and W. C. Davison, Enzymes. Williams and Wilkins Co. 



Baltimore, 1926. 

 Waldschmidt-Leitz, E. Enzyme actions and properties. Translated by 



R. P. Walton. John Wiley and Sons. New York. 1929. 

 Warburg, O. Katalytische Wirkungen der lebendigen Substanz. Julius 



Springer. Berlin. 1928. 

 Willstatter, R. Untersuchungen ilber Enzyme. 2 vol. Julius Springer. 



Berlin. 1928. 



Selected Bibliography 



Balls, A. K., H. Lineweaver, and R. R. Thompson. Crystalline papain. 



Science 86: 379- 1937- 

 Brown, H. T., and F. Escombe. On the depletion of the endosperm of 

 Hordeum vulgare during germination. Proc. Roy. Soc. (London) B. 



63: 3-25- 1898. 

 Brown, H. T., and G. H. Morris. Researches on the germination of some 



of the Gramineac. Jour. Chem. Soc. (London) 57: 458-528. 1890. 

 Davison, F. R., and J. J. Willaman. Biochemistry of plant diseases. IX. 



Pectic enzymes. Bot. Gaz. 83 : 329-361. 1927. 

 Granick, S. Urease distribution in Canavalia ensiformis. Plant Physiol. 



12: 601-623. 1937- 

 Grassmann, W. Proteolytische Enzyjue des Tier- und Pflanzenreiches. 



Ergebn. Enzymforsch. i: 129-167. 1932. 



