402 Effect of Salicylic Aldehyde on Plauts [April-July 



experiment when no calcium carbonate was used. The tops, how- 

 ever, were still much affected in the carbonate cultures. 



From these experiments under alkaline conditions it is seen that 

 the harmfulness of salicylic aldehyde can not be attributed to any 

 slight acidity it may possess. There is some indication that calcium 

 carbonate ameliorated its effects. 



EXPLANATION OF PLATES 



Skinner: Effect of salicylic aldehyde on plants in soil, and 



solution cultures 



Plate 6 



Fig. i: Effect of salicylic aldehyde on wheat seedlings in water sol. (i) 

 Control in dist. water; (2) same, plus salicylic aldehyde, 10 p.p.m. ; (3) 25 p.p.m. ; 

 (4) so p.p.m.; (5) 100 p.p.m.; (6) 200 p.p.m. 



Fig. 2: Effect of salicylic aldehyde on com plants in nutrient sol. (i) Con- 

 trol in nutrient sol.; (2) same, plus salicylic aldehyde, 10 p.p.m.; (3) 25 p.p.m.; 

 (4) 50 p.p.m.; (5) 100 p.p.m.; (6) 200 p.p.m. 



Fig. 3: Effect of salicylic aldehyde on cowpea plants in nutrient sol. (i) 

 Control in nutrient sol.; (2) same, plus salicylic aldehyde, 10 p.p.m.; (3) 25 

 p.p.m.; (4) so p.p.m.; (s) 100 p.p.m. ; (6) 200 p.p.m. 



Fig. 4: Effect of salicylic aldehyde on cabbage plants in nutrient sol. (i) 

 Control in nutrient sol.; (2) same, plus salicylic aldehyde 10 p.p.m.; (3) 25 

 p.p.m. ; (4) SO p.p.m. 



Plate 7 



Fig. 5: Effect of salicylic aldehyde on v^eat in soil. (i) Clay loam un- 

 treated; (2) same, plus salicylic aldehyde, 10 p.p.m.; (3) 25 p.p.m.; (4) 50 

 p.p.m.; (5) 100 p.p.m. 



Fig. 6: Effect of salicylic aldehyde on com in soil and in sand. (A) — Clay 

 loam soil: (i) Untreated; (2) salicylic aldehyde, 50 p.p.m.; (B) — Sand: (i) 

 Untreated; (2) salicylic aldehyde, 50 p.p.m. 



Fig. 7: Effect of salicylic aldehyde on clover in soil. (i) Soil untreated; 

 (2) soil with a total of 100 p.p.m. of salicylic aldehyde. 



