190 



M. M. McCooL 



N/100 MnCl2 is likewise very toxic to tops, and to a less extent to 

 roots, of seedlings. Chlorosis of the leaves soon appears in this culture. 

 The presence of either N/10 or N/50 CaCl2 appreciably counteracts this 

 deleterious action, the loss of green color being then scarcely apparent. 



The development of the roots in solutions of N/200 MnCl2 is almost as 



Fig. 13. — Antidotal relations between calcium and manganese; nutrient solution as the solvent 



1. 



N/10 CaCl2+N/50 MnCl2 



8. 



N/50 CaCl2 



2. 



N/10 CaCl2+N/100 MnCl2 



9. 



N/100 CaCl2 



3. 



N/10 CaCl2+N/500 MnCk 



10. 



N/500 CaCl2 



4. 



N/50 CaCl2+N/500 MnCl2 



11. 



N/50 MnCb 



5. 



N/100 CaCl2+N/500 MnCk 



12. 



N/100 MnCl2 



fi. 



N/500 CaCl2+N/50 MnCh 



13. 



N/500 MnCl2 



7. 



N/10 CaCh 



14. 



Nutrient solution 



extensive as in the control cultures. The length of the stems is about 

 one half that of those grown in the nutrient solution. The presence of 

 N/500 CaCb results in a slight increase in elongation of the stems. The 

 detailed data obtained appear in Table 9: 



