132 PERMEABILITY 



7. An algal filament is immersed in a dilute glycerol solution and the solution 



allowed to lose water by slow evaporation. Even when the solution has 

 attained a concentration of about 50 per cent glycerol the filament shows 

 no evidence of plasmolysis. Explain. If the filament is then transferred 

 into pure water it swells and bursts almost immediately. Explain. 



8. Why does NH4OH apparently penetrate into many plant cells more readily 



than most other bases? 



9. How do you account for the finding that when a NH4CI solution is injected 



into a plant cell the cell sap becomes more acid, but if the cell is immersed 

 in a NH4CI solution the cell sap becomes more alkaline? 



10. How would you determine whether or not the cytoplasm of a root hair cell 



is permeable to sucrose? 



11. What evidence is there in support of the view that the tonoplast and plas- 



malemma are chiefly responsible for the differential permeability of the 

 cytoplasm? 



12. How could you demonstrate the effect of temperature variations upon the 



permeability of the protoplasm of a living cell to a certain solute within 

 the range of 10-40° C? 



Suggested for Collateral Reading 



Bayliss, W. M. Principles of general physiology. 4th Ed. Longmans, Green 



and Co. London. 1924. 

 Cowdrey, E. V., Editor. General cytology. (Section III by M. H. Jacobs) 



Univ. Chicago Press. Chicago. 1924. 

 Osterhout, W. J. V. Injury, recovery, and death in relation to conductivity 



and permeability. J. B. Lippincott and Co. Philadelphia. 1922. 

 Scarth, G. W., and F. E. Lloyd. An elementary course in general physiology. 



John Wiley and Sons. New York. 1930. 

 Seifriz, W. Protoplasm. McGraw-Hill Book Co. New York. 1936. 

 Stiles, W. Permeability. Wheldon and Wesley Co. London. 1924. 



Selected Bibliography 



Bonte, H. Vergleichende Permeabilitatsstudien an Pflanzenzellen. Proto- 



plasma 22: 209-242. 1934- 

 Brooks, M. M. Studies on the per?neability of living cells. Fill. The 



effect of chlorides upon the penetration of dahlia into Nitella. Proto- 



plasma 2: 420-427. 1927. 

 Chambers, R., and K. Hofler. Micurgical studies on the tonoplast of Allium 



cepa, Protoplasma 12: 338-355. 1931. 

 Collander, R. Permeability. Ann. Rev. Biochem. 6: 1-18. 1937. 

 Haan, I. de. lonenwirkung und IFasserpermeabilitdt. Protoplasma 24: 186- 



197. 1935. 

 Iljin, W. S. Die Durchldssigkeit des Protoplasmas. Protoplasma 3 : 558-602. 



1928. 

 Jacobs, M. H. Per?neability. Ann. Rev. Biochem. 4: 1-16. 1935. 

 Lepeschkin, W. W. Light and the permeability of protoplasm. Amer. Jour. 



Bot. 17: 953-970. 1930. 



