988 



THE LIGHT FACTOR. I. INTENSITY 



CHAP. 28 



plants (fig. 28.17) or single leaves (fig. 28.18). The figures in Table 28.IV 

 further show that the respiration of sliade-adapted plants is weaker than 

 that of the sun-adapted specimens. 



Fig. 28.17. Light curves of photosynthesis of shade plates (S) and sun plants 

 (L) of the same species (after Gessner 1937). Former saturated at 40 klux; latter 

 onlv far above 80 klux. 



9 II 13 15 20 30 40 



klux 



Fig. 28.18. Light curves of sun leaf (a) and shade leaf (b) of 

 Fagus silvatica (after Boj^sen-Jensen and Miiller 1929). Former 

 saturated at or above 30 klux; latter at 3 klux. 



