TRACE ELEMENTS IN PLANTS 117 



Table XIII. Absorption of calcium by Vicia Faba from 

 nutrient solutions with and without boron. (Data from 

 Warington) 



Age of Total calcium absorbed mg. per plant 



plant in <— A ■ s 



weeks With boron Without boron 



1930 series: Solutions not renewed 



2 2-2 2-6 



3 8-3 51 



4 151 71 



5 251 6-6 



1931 series: Solutions not renewed 



2 2-2 2-2 



3 6-2 3-5 



4 13-8 5-5 



5 171 GO 



Solutions renewed fortnightly 



5 17-8 101 



9 50-9 15-6 



Solution renewed weekly 

 9 54-83 26-65 



Table XIV. Absorption of calcium by Glycine hispida from 

 media containing various amounts of boron. (Data from 

 Minarik and Shive) 



Average fresh Calcium in 



obtained up to that time with these various species. Plants were 

 grown in sand cultures and for the first week were supplied with 

 a nutrient solution containing all necessary elements except 

 boron, this being omitted so that any in the seed or in external 

 sources should be exhausted. During the second week all the 



