19 



INJURIOUS EFFECTS OF CHLORIDS ON PLANTS. 



However necessary may be the presence of a certain amount of a 

 chloric! for buckwheat and probably for many other plants, very unde- 

 sirable results are produced when it is increased beyond a certain point, 

 owing to the fact that the solution of starch might be facilitated in 

 organs the value of which depends on their starch content, as in pota- 

 toes. Sljould it prove to be correct that the chlorids favor the forma- 

 tion of cellulose from sugar, then the decrease of the sugar content in 

 the sugar beet on account of the influence of chlorids would also be 

 explained. On the strength of this hypothesis it might also be inferred 

 that woody growth would be increased by supplying trees with moder- 

 ate doses of chlorids. 



To decide the physiological value of chlorids, plants of other fami- 

 lies should also be cultivated in the presence of an abundance of potas- 

 sium nitrate alone and in combination with potassium chlorid and 

 sodium chlorid. Beyer's^ experiments with peas and oats are not con- 

 vincing in this regard, as anyone must infer who compares the compo- 

 sition of his main and control solutions. 



An increase of sodium chlorid beyond a certain point has a retarding 

 influence upon assimilation in the chloroplasts (Schimper). Coupin^ 

 has determined for several plants the amounts that would be injuri- 

 ous; e. g., a solution of 1 per cent will retard the growth of wheat and 

 a solution of 1.8 per cent will prevent its germination. Sodium chlorid 

 reduces the amount of chlorophyll in plants of the seacoast region, but 

 causes the leaves to increase in thickness. The intensity of assimila- 

 tion of carbonic acid is less in plants on the seacoast than in such 

 plants growing farther inland (Griffon). Certain algae, such as Spiro- 

 gyra crassa^ will suffer in culture solutions containing 0.5 per cent potas- 

 sium or sodium chlorid, while lower kinds are not affected by 1 per cent 

 chlorid of sodium or even more, and certain bacteria and small yeasts 

 can even grow in the i^resence of from 10 to 12 per cent. 



ABSORPTION OF CHLORIDS BY AQUATIC PLANTS. 



The considerable absorptive power of many aquatic plants for chlorids 

 is interesting. The ash of Nymphcva alha^ amounting to 7 to 10 per cent 

 of the dry matter, was found to contain 9 to 23 per cent of chlorine 

 and that of Spirogyra nitida 24 per cent. The ash of such plants does 

 not always show a sufficient potassium content to bind all the chlorine 

 present, hence a part of the latter will in such cases be present as 

 sodium chlorid. In order to estimate the absorptive power of Elodea 

 canadensis^ the writer has determined the amount of chlorine in water 

 which ran slowly through a basin in which this plant was cultivated, 

 and found that besides some sulphate and calcium and magnesium 

 bicarbonate the water contained, per liter, 4.5 mgr. chlorine, 1.6 mgr. 



iLandw. Vers. Stat., 1869, p. 262. 



2 Revue Geuerale de Botanique, Vol. X, p. 177. 



