232 



EXPERIMENT STATION RECORD. 



SEEDS— WEEDS. 



On the influence of arsenic on the germination of seeds, B. 



JoNSSON (A7//. Landt. Almd. HamU., 35 {1S96), 2)p. 9 5- 11 3). —The iiitlii- 

 eijce of arsenic on the growth of plants has been studied by NoV)be,' 

 Jager,- and Lyttkens,^ and in eveu tbe very dilute solution of one 

 part of arsenic in one million a deleterious influence lias been observed. 

 Lyttkens lias suggested that the arsenic content of superphosphates, 

 which frequently anunmts to about 0.1 per cent or more of arsenious 

 acid, may in many cases account for a decrease in yields which has 

 been laid to unfavorable chinatic conditions, etc. 



The author investigated the effect of the presence of arsenic in the 

 germinating bed on the viability and the germinative energy of difi'er- 

 ent kinds of seeds. The experiments were conducted with clover and 

 various grass seeds, partly under bell glasses and partly in paper 

 envelopes, the details being fully described. 



The average germination observed was higher in the arsenic series 

 than where the seeds were germinated on arsenic-free paper in every 

 case but one. The author explains these results by the antiseptic 

 action of arsenic upon the injurious organisms. Microscopic exami- 

 nations showed that the germination paper containing arsenic was 

 freer from foreign organisms than the arsenic-free pai)er. 



In experiments with seeds kept in paper envelopes or covered with 

 paper under bell jars, where the arsenic of the paper came in close con- 

 tact with the seeds, a distinct arsenic poisoning Avas observed, the 

 average decrease in the viability of seeds jn the arsenic series being 

 4.4 per cent. The greatest average decrease for any one kind of seed 

 was 15 per cent in a series of 5 trials with timothy. 



The form in which arsenic was found in the paper used in the experi- 

 ments could not be ascertained, on account of the small quantities 

 present. Some experiments made with red-clover seed show that 

 arsenious acid has a more marked effect in decreasing the viability of 

 seeds than has arsenic acid, as is evident from the data given in the 

 following table: 



Germination experiments with red-clover seed. 



ConceiitratioTi of 

 li(liiid. 



Germination bed impregnated with— 



Arsenious acid. 



100.... 

 500.... 

 5,000.. 

 50,000 . 

 500,000 



Viable 



Hard 

 seeds. 



Per cent. 

 CO 

 16.0 

 20.0 

 62.0 

 78.0 



Percent. 

 3.0 

 3.0 

 4.0 

 4.0 

 3.5 



Non- 

 viable 

 seeds. 



Per cent. 

 91.0 

 81.0 

 76.0 

 34.0 

 18.5 



Arsenic acid. 



Arsenic free germination 

 bed. 



Viable 

 seeds. 



Hard 

 seeds. 



Per cent. I Per cent. 

 20. 3. 



42.5 

 67.0 

 88.0 

 92.5 



4.5 

 3.0 

 3.5 

 5.0 



Non- 

 viable 

 seeds. 



Viable 



Hard 

 seeds. 



Percent., Per cent. .Per cent. 



77.0 



53.0 



30.0 



8.5 



2.5 



98.0 

 96.0 

 95.0 

 94.0 

 96.0 



2.0 

 4.0 

 3.5 

 5.0 

 4.0 



Non- 

 viable 

 seeds. 



1.5 

 1.0 



' Laiulw. Vers. Stat., 30 (1884), pp. 381-436. 



- Ueber die Wirkuug- des Arseiiiks auf Pflauzeu, Stuttgart, 1864. 



=*Kgl. Laudt. Akad. llaiidl., 18D1 (E. S. R., 5, p. 1011). 



