KEARNEY: PLANT LIFE ON SALINE SOILS 123 



of numerous cultural experiments. The results are contra- 

 dictory even, in some cases, when the same species was used by 

 different experimenters. Unquestionably, certain species that 

 in nature are confined to saline soils, will not only thrive but 

 grow more vigorously in the absence of a noteworthy quantity of 

 salt, although the appearance and structure of the plants may 

 be materially altered. 



Batalin claimed that even such an extreme halophyte as 

 Salicornia herhacea can be grown successfully in ordinary gar- 

 den soil, watered with river water. On the other hand, Peklo^- 

 found that this plant soon died in a Knop nutrient solution, 

 which contains no sodium, but flourished in the same solution 

 plus 2 per cent of sodium chloride. Similar results with other 

 species of Salicornia were obtained by Miss Halket. 



The published data on cultural experiments which indicate 

 that sodium salts are important to halophytes, do not permit 

 a conclusion to be drawn as to whether the limiting factor is the 

 presence of the element sodium or merely a high total concen- 

 tration in the medium. It would be interesting to know whether 

 the results with Salicornia in water cultures would have been 

 equally satisfactory, if the salt added in excess to the nutrient 

 solution had been potassium chloride, instead of sodium chloride. 



In order to determine definitely whether the salt plants can 

 completely dispense with sodium, it would, of course, be neces- 

 sary to insure the absence of any trace of the element, in both 

 plant and culture medium. Since sodium is known to occur 

 even in the seeds of halophytes, this experimental condition is 

 probably impossible to realize. 



SODIUM IN PLANT NUTRITION 



Consideration of the physiology of halophytes brings up the 

 question, what, if any, is the role of sodium in plant nutrition? 

 Osterhout^^ states that this element, because of its protective or 

 antagonistic action, is essential to the maintenance of life in 



*'^ J. Peklo. Bemerkungen zur Erndhrungsphysiologie einiger Halophyten. 

 Oesterr. Bot. Zeitschr. 62: 47, 114, 172. 1912. 



" W. J. V. OsTERHOUT. Plants which require sodium. Bot. Gaz. 54: .532. 

 1912. 



