THE METABOLISM OF PLANTS. 



259 



The following table gives an account of the different kinds of ash- 

 constituents absorbed in light of different colours. In each case 100 

 seedlings were analysed, and the weights given are in grammes. 



It will be noticed that when the plants were exposed to those rays of 

 light (impure yellow) which, as we have seen, are the most active in 

 promoting constructive metabolism, the essential ash-constituents are 

 absorbed in largest quantity. 



172 



