186 



M. M. McCooL 



TABLE 6. 



ExPERIifENT WITH CaNADA FiELD PeA, CONTINUED FOR THIRTY DaTS. 



FOR Ten Plants 



Data 



Composition of solution 



N/10 CaCI. 



N/25 CaCl. 



N/100 CaCl2 



N/500 CaCl2 



N/1,000 CaCU 



N/2,000 CaCl2 



N/4,000 CaCl2 



N/10 CaCl2+N/100 MnCU . . . 

 N/10 CaCl2+N/500 IMnCU. . . . 

 N/10 CaCl2+N/ 1,000 INInCh. . 

 N/10 CaCl2+N/2,000 MnCh. . 

 N/10 CaCl2+N/4,000 :MnCl2. . 

 N/25 CaCL+N/1,000 ^InCU. . 

 N/100 CaClo+N/1,000 MnCU. 

 N/500 CaCl2+N/1.000 MnCU. 

 N/2,000 CaCl2+N/l,000 MnCl 

 N/4,000 CaCl2+N/l,000 MnCl 



N/1,000 MnCl2* 



N/4,000 MnCl2 



Distilled water 



Green 

 weight 

 of tops 

 (grams) 



Green 

 weight 

 of roots 

 (grams) 



5.90 

 7.10 

 6.95 

 6.20 

 6.65 

 5.25 

 4.25 

 2.94 

 5.46 

 5.12 

 5.15 

 5.76 

 4.52 

 5.56 

 3.75 

 3.45 

 2.01 



1.80 

 1.85 



6.15 

 5.05 

 4.45 

 4.00 

 3.20 

 2.47 

 2.10 

 5.06 

 5.81 

 6.92 

 6.20 

 4.10 

 4.20 

 4.10 

 3.50 

 3.05 

 2.40 



1.64 

 1.75 



Total 



green 



weight 



(grams) 



Average 

 length 

 of tops 

 (centi- 

 meters) 



Average 

 length 



of roots 

 (centi- 

 meters) 



*Weight not taken. Practically no growth. Dead. 



As is brought out in the above table, calcium is effective in overcoming 

 the harmful properties of manganese. It is to be noted that solutions 

 of N/10 CaCl2 reduce the deleterious action of various amounts of this 

 mineral element. The greatest development of plants (in mixed solutions) 

 occurs in cultures composed of N/10 CaCla+N/lOOO MnCla. In N/10 

 CaCl2+ N/100 MnCl2 the toxicity of the manganese toward the tops is 

 not reduced to such an extent as it is toward the roots. The plants in 

 this culture were somewhat chlorotic. It is to be noted further that a 

 very slight amount of calcium (N/4000 CaCl2) reduces the injury caused 

 by N/1000 MnCl2. In no case has the addition of manganese to a solution 

 of calcium resulted in an increased development of plants over that in 

 the corresponding solutions of calcium alone. 



The relation of -previous conditions of growth to antidotal relations between 

 calcium and manganese. — In order to determine whether the age of seed- 



