SEEDS WEEDS. 657 



affected, and completely killing the others; while the 0.4 per cent scjlution destroyed 

 all seeds except the maize. 



Germination of wheat treated with copper sulphate, E. Demoussy {Ann. 

 Agron .,27 { 1901 ) , Xo. 6, pp. 257-261 ). — On acconnt of recently published investigations, 

 which showed the injurious action of extreme dilutions of copper and other salts, the 

 author was led to study the effect of fungicides upon plants and to ascertain the 

 reasons for the comparatively slight injury upon foliage and seeds when treated with 

 fungicides containing an amount of copper far in excess of the minimum toxic 

 strength. In the case of fungicides sprayed upon plants, the injurious action is 

 neutralized by the presence of carbonate of lime, or other alkalis. Where seeds are 

 soaked or wetted with strong solutions, the reason for the limited injury is not so 

 evident. 



The author conducted a number of experiments in which wheat was soaked in 

 solutions of copper sulphate and determinations afterwards made of the copper 

 adhering to the seed. In ordinary practice the strength of the solution employed is 

 1 kg. of copper sulphate dis.solved in a hectoliter of water, or 0.253 gm. metallic cop- 

 per per 100 cc. of water. In the first of the author's experiments, 25 gm. of wheat 

 were immersed in 50 cc. of the above solution, and after 15 minutes' immersion the 

 weight of the copper remaining in the solution was practically undiminished. In a 

 second case, the amount of metallic copper in the solution fell from 0.251 to 0.248 

 gm. After treatment 25 gm. of seed wheat were dried, incinerated, and the amount 

 of copper adhering was found to be 0.011 gm. After washing treated seed three 

 times, the copper still adhering was 0.009 gm. Other investigations showed that the 

 copper was wholly deposited on the outside of the grain, at least none could be 

 detected by potassium ferrocyanid tests within the seed coats. Germination tests 

 were made of 6 lots of wheat, of 5 gm. each, practically 100 seeds each. Two lots 

 were simply dipped into the copper solution; 2 soaked for 15 minutes; and 2 soaked 

 for the same length of time, after which the grain was wastied in 3 waters; and all 

 germinated under similar conditions, with a check lot untreated. A retarding action 

 wai! noted for all treated lots. If the treated seeds were germinated upon filter 

 paper no injurious action was noted, and similar results were obtained for 6 lots of 

 seed germinated in pots containing soils, some of which contained lime and others 

 without. In explaining this lack of injury, the author claims the capillary action of 

 the filter paper and soils drained the copper from the seed, and as a result the tender 

 radicles did not come in contact with a toxic quantity of the metal. The suggestion 

 often given, that seed treated with coi)per sulphate should afterwards be limed, he 

 believes to be unnecessary in ordinary practice, his experiments having shown 

 equally well for those lots which received no lime. The physical character of the 

 soil seems sufficient to overcome the injurious action of the salt when used in ordi- 

 nary strengths. 



Stimulating the germination of teak seed ( Trop. A(jr., 20 {1900-1901), p. 176). — 

 It is stated that the usual time required for germinating seed of teak varies from 2 to 

 3 months. Experiments which have been undertaken show that this time may be 

 greatly shortened in different ways. One experiment was carried out in which the 

 seeds were placed in a shallow pit, which was afterwards filled with water, and sub- 

 sequently the seeds were kept moist by being watered every 4 days. In the second 

 experiment the seeds were soaked for 24 hours in warm water before planting. In 

 both exi>eriments the time of germination was reduced to a few days. 



Deciduous tree seeds, G. W. Stk.\nd {Florists' Exchange, 13 {1901), No. 14, 

 p. 379). — Directions are given for the collection and management of tlie seeds of a 

 number of deciduous forest 'trees. The seeds of willows, soft maples, poplars, and 

 elms — with the exception of the red elm — should be sown on ground that remains 

 reasonably moist, as soon as possible after gathering, as they lose their germinating 

 power very quickly. The depth to which seeds should be covered varies with differ- 



