Svensk Botanisk Tidskrift. 1921. Bd. 15, H. 1. 



ECOLOGICAL STUDIES IN THE ASSIMILATION 



OF CERTAIN FOREST-PLANTS AND 



SHORE-PLANTS. 



BY 



HENRIK LUNDEGÅRDH. 



CONTRIBUTIONS FROM HALLANDS VÄDERÖ ECOLOGICAL STATION. N:o 4 



1. Introduction. 



In Ihe sludy of Ihe carbon dioxide assimilation Ihe altention has 

 been directed pailly upon Ihe invesligalion of Ihe inlernal conditions 

 and Ihe chemical nalure of the process, and parlly upon Ihe de- 

 duction of Ihe external faclors aflecling Ihe course of Ihe assimilation. 

 Among the inost important of the chemical works dealing with the 

 carbon dioxide assimilation must undoubledly be mentioned the 

 researches of Willstätter and Stoll (1913, 1918). Our knowledge 

 of the externat conditions has been carried a great step forwards 

 more particularly by the labours of Blackman and his collabo- 

 rators. 



According to our present knowledge the assimilation is subject 

 to the foUowing conditions: — 1, the amount of chlorophyll and 2, 

 a protojilasm faclor (the »assimilation enzym» of Willstätter and 

 Stoll [191(Sj), which together form the internal factors, and 3, the 

 amount of carbon dioxide, 4, the amount of water, 5, the supply 

 of light, and 6, the temperature, which together make up the external 

 factors. 



In regard to the reciprocal inlluence of the various external factors 

 the theory put forward by Blackman seems to be generally adop- 

 ted. According to Blackman (1905, Blackman and Matthaei 1905, 

 Blackman and Smith 1911), the factor present in the minimum 



