VOLUME LXIII 









NUMBER 4 



THE 



Botanical Gazette 



APRIL 1917 



ENVIRONMENTAL INFLUENCES ON NECTAR 



SECRETION 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 228 



Leslie A. Ken oyer 



This study was undertaken to summarize and supplement exist- 

 I ing knowledge of the factors which stimulate or retard the secretion 



1 of nectar. The work was carried out under the direction of the 



botanical section of the Iowa State Experiment Station in coopera- 

 tion with the chemical section, being done mostly at Ames, Iowa, 



A 



from June 1914 to June 1916. 



Historical 



with 



nvironmental 



tion, was written by Bonnier (i). The subject of secretion has 

 been much debated from a physical standpoint. Godlewski (9) 

 attributes it to a fluctuation in the concentration of the cell sap 

 due to alternate splitting and recombination of complex molecules. 

 Pfeffer (19) advances 3 possible causes for secretion: (1) an 

 unequal permeability of the membrane of the absorbing and 

 excreting portions of the cell; (2) an unequal distribution of solutes 

 in the absorbing and excreting portions of the cell; (3) the trans- 

 formation into sugar of the outer portion of the cell wall, and the 

 osmotic action of this sugar upon the liquid contents of the cell. 

 Lepeschkin (14), in a study of the coenocytic plant Pilobolus, finds 



249 



