80 PROTECTION OF PLANTS — 1923-24 



Scope of Investigations. 



The present studies were carried on in the Department of Botany, at 

 Macdonald College, Mc Gill University, during the second term of 1922-23, and 

 the second of 1923-24. They were thus of necessit}^, confined to the laboratory 

 and green-house tests. 



The following factors were considered : 



1. Effect of varying strengths of formalin solution. 



2. Effect of duration of treatment. 



3. Effect of temperature of treatment solution. 



4. Effect of carbon dioxide on the germination of treated seed. 



5. Effect of presoaking before formalin treatment. 



6. Relation of soil moisture to formaldehyde injury with limed and unlimed 

 seed. 



7. Effect of dry sto^'age after treatment. 



9. Comparison of the effects of different smut treatments. 



It was planned to study the permeability of seed coats, and the effect of 

 soil temperature on treated seed, but time did not allow the satisfactory under- 

 taking of the work. 



Historical Account of Seed Injury. 



The injurious effects of fungicides upon the vitality" of seeds have been 

 studied by numerous investigators in various countries. Most of the investiga- 

 tions along this line have taken place in recent years. However, observations 

 regarding injury have been made at irregular intervals for a half century. The 

 results of some investigators are given below in chronological sequence. 



Isidore, in 18 76, found that seeds of wheat dipped in boiling milk of lime 

 for two or three minutes lost the power to germinate; 54 per cent of the seeds 

 germinated after being dipped for three minutes in a solution of 2 per cent 

 copper sulphate, at 60 C, and 63 per cent at 50 C. 



In 1891, Arthur observed that, when oats were treated with copper sulphate 

 the plumules emerged earlier than the rootlets. This was due to "the fact 

 that the primary roots were killed before starting and the secondary ones, 

 which took their places, were consequently late in appearing". 



Bolley, in 1895, stated that wheat dusted vvith air-slaked lime after having 

 been sp'-inkled with a copper sulphate solution, was not reduced in germina- 

 tion to the same extent as seed treated with a copper sulphate solution alone. 



In 1899, David ascertained that the degree of injury by formaldehyde 

 varied with the different cereals, and was in direct pi'oportion to the strength of 

 solution and the duration of treatment. The seed injury was manifest in a 

 retarded and abno»'mal germination in which no roots were produced. The 

 injurious effects of the formaldehyde were reduced by soaking for fifteen minu- 

 tes in a weak eohition of ammonia. 



