303 



does not possess the ability of re-dissolving the calcium already deposited in 

 old tissues in appreciable amounts and transporting it where it can instantly 

 become effective for new structures, when there is a lack of calcium. At 

 least the experiments of Bohm\ Raumer and Kellermann- and Benecke'^ 

 prove that no calcium, or very little passes from the containers of reserve 

 substances into the young tissues when the plants are grown in distilled 

 water, in solutions free from calcium, or in quartz sand. The fact that no 

 calcium is necessary for the formation of starch itself has been proved by 

 ^Bohm. He found that primordial leaves free from starch with shrivelled 

 petioles became filled with starch when grown without lime, but under 

 otherwise favorable conditions. In order to dissolve the reserve substance 

 and to transport it chemical combination with calcium is necessary, for an 

 investigation of plants grown in media lacking calcium proved that the 

 organs (leaves, cotyledons) had not given up all the starch, the leaf body 

 or the adjacent internodes retained considerable quantities, while the young 

 plant starved to death despite its sugar content. My own experiments* also 

 led to the conclusion that the plant needs new mineral substances originating 

 from the solution in the soil, even at a time when it is working up the re- 

 serve material into cellulose, etc. 



Thus in the germination of seeds an addition of calcium acts bene- 

 ficially; in fact, it often seems necessary. The statement that calcium is 

 disadvantageous for germinating seed^ may have arisen from a use of too 

 highly concentrated solutiors. Loew and May declare that definite excess 

 of calcium in the soil over the magnesium content can produce starvation 

 symptoms in the plant (see Lack of Magnesium). An earlier assertion of 

 Deherain and Breal*' that, with a lack of calcium the plants can better 

 utilize the lime stored in their bodies, if the temperature is raised, has 

 not held". Molisch, as well as Portheim, has also proved the error of these 

 statements^. 



Among the older observers®, Nobbe describes the phenomena due to a 

 lack of calcium in water cultures. Buckwheat, peas, Robinia, etc., grew but 

 little beyond the germinating stage. The pale leaves exhibited spots, simi- 

 lar to these produced by the action of acid, which dried up gradually, and 

 then the petioles often broke. On conifers, the tips of the first year needles 

 became yellow to brown. 



1 Bohm, tJber den veg-etabilischen Nahrwert der Kalksalze. Sitzungsber, d. k. 

 Akad. d. Wissensch., Vol. 71, 1875, p._ 287 ff. 



2 V. Raumer and Kellermann. tJber die Funktion des Kalks im Leben der 

 Pflanze, Landwirtsch. Versuchsstationen XXV, 1880, Parts 1 and 2. 



3 Benecke, W., Uber Oxalsaurebildung- in grijnen Pflanzen. Bot. Zelt. 1903, Part 5. 



4 Sorauer, Studien fiber Verdunstung. Forsch. auf d. Geibiete d. Agrikultur- 

 f hysik. 1880, p. 429. 



5 Windisch, R., tJber die Einwirkung des Kalkhydrates auf die Keimung-. 

 Landwirtsch. Versuchsstationen. 1900, p. 283. 



6 Annales agronomiques. Vol. IX, 1883, No. 52. 



7 Kriiger, W., und Schneidewind, W., Zersetzungen und Umsetzungen von Stick- 

 stoffverbildungen im Boden durch niedere Organismen, etc. Landwirtsch Jahr- 

 bucher, 1901, p. 633ff. 



8 V. Portheim, L., tJber die Notwendigkeit des Kalkes fur Keimlinge. etc 

 Cit. Bot. Jahresber. 1901, Section II, p. 141. 



9 Dobner-Nobbe, Botanik fur Forstmanner. 1882, p. 314. 



