7o 



U. SUZUKI. 



precipitating the oxalic acid produced in the cells, then such 

 elements as strontium and barium, which form insoluble salts 

 with oxalic acid, must prove equally available as calcium. On 

 the contrary, if lime is an integral part of the nucleus and 

 chlorophyll-bodies, then, as Loew says, it can never be replaced 

 by other elements. This is a point which needs a thorough 

 elucidation. 



In 1893, some experiments on this lime was made by 

 Haselhoff,* who concluded that strontium can replace calcium 

 in phaenogams. But he cultivated his plants in a fertile soil, 

 which contained naturally much lime, and also in his water 

 culture, he added strontium-salts together with lime. Hence 

 we can not be surprised that he observed no injurious effects. 

 Loew holds the view that when strontium is used together with 

 lime, then the plants will by elective absorption take up much 

 more lime than strontium, and can exchange small doses of 

 strontium taken into organic structures always against the lime 

 present in solution. His observations on the poisonous action 

 of oxalates upon plant-cells under the microscope led him to the 

 view that the calcium is present in the nucleus and chlorophyll 

 bodies in organized protein compounds, as above mentioned. 

 But if strontium-salts alone are offered to the plant, then the 

 effect must be quite different. In accordance with this view, he 

 made two experiments with young branches of Tradescantia 

 repens, and found that the poisonous action of strontium is, to 

 a large extent, masked by the presence of lime, but that as soon 

 as the lime content is diminished to a certain degree, then the 

 poisonous effect of strontium-salts becomes at once apparent 

 As this question appeared very interesting I have made also 

 experiments with five species of phaenogams. The results of 

 these experiments will be described in the following pages : — 



•Haselhoff; — (Landw. Jahrbucher. Bd. XXII. 1893. S. 851.) Mis conclusion is 

 as follows : — 



1) Das Strontium wirkt nicht schadlich auf die Pflanzenentwickelung. 



2) Das Strontium wird von der Pflanze anfgenommen und scheint bei dor Ernahr- 

 ung die Stelle des Kalks zu vertreten. 



3) Diese Substitution des Kalks durch Strontium bei der Pflanzenernihrung 

 scheint aber erst dann einzutretcn, wann der Vorratb an Kalk und anderen 

 Nahrstoffen nicht mehr zum Aufhau der pflanzlichen Organismen ausreichen. 



