SEED GERMINATION 45 



Miss Magowan (19) states that alkali experiments are 

 not reliable when they are continued only a week because 

 the relative toxicity of the salts may change later. She 

 found that although magnesium chloride was at first the 

 most toxic of the chlorides, followed by sodium chloride, 

 potassium chloride, and calcium chloride, this relation- 

 ship did not hold throughout the experiment. 



Working with wheat seedlings in solutions of 0.01 normal, 

 or 585 parts per million, sodium chloride, 850 parts per 

 million sodium nitrate, 746 parts per million potassium 

 chloride, and ion parts per million potassium nitrate, 

 Micheels (21) found chlorine more harmful than nitrate 

 ions, and sodium more harmful than potassium ions. He 

 ascribed the variation to physiological and not chemical 

 differences, as did also Slosson and BufTum (27) working 

 with wheat, rye, and beans in the common alkali salt 

 solutions. Sodium carbonate was the only salt found 

 causing other than physiological injury. 



Wyoming experiments (27) show the highest concentra- 

 tion of salts not retarding germination of wheat and rye 

 to be as follows: 



MgS0 4 Na 2 S0 4 NaCl Na 2 C0 3 



Wheat 10,000 7000 4000 4000 



Rye 10,000 7000 4000 1000 



The vitality and time to germinate were effected dele- 

 teriously as the strength increased above the minimum. 

 Rye was as a general rule more tolerant of the higher 

 concentrations of these salts than was wheat. 



Sigmund (26) found 5000 parts per million of sodium 

 chloride or of sodium carbonate retarded the germination 

 of cereal seeds in solutions of these salts. Vetch and 

 rape seeds were killed in 5000 parts per million solutions 



