47] Stoffaufnahme. Allgemeines 303 



302. Farnsky, F. Das Chlorbedürfnis einiger Kultur- 

 pflanzen. (Ztschr. lanoV. Versuchswesen Österr. 21, 1918, p. 161 — 201.) — 

 Eef. in Bot. Ctrbl. 140, 1919, p. 221. 



303. Fernglio, 1). L e ceneri d i 1 e g n a. (Le Staz. sper. agrarie 

 ital. 51, 1918, p. 220—227.) — Es handelt sieh um den Gebrauch der Holz- 

 asche als Kalidünger in Italien während des Weltkrieges. 



A. Borntraeger. 



304. Fischer, Hermann. Über Verhalten u n d W i r k u n g eini- 

 ger künstlicher und natürlicher Phosphors ä u r e d ü n g e - 

 mittel in Teichen. (Ztschr. f. Forst- u. Landwirtschaft 15, 1917, p. 128 

 bis 146, mit 3 Kurven.) 



305. Fischer, Hermann. Das Problem der Stickstoffbin- 

 dung (Festlegung des Luftstickstoffs) bei niederen 

 Pflanzen. (Ber. D. Bot. Ges. 35, 1917, p. 423—454.) — Ref. in Bot. Ctrbl. 

 141, 1919, p. 323—324. 



306. Frodin, J. Über nitrophilePflanzenfor m a t i o n e n auf 

 d e n A 1 m e n J ä m 1 1 an d s. (Bot. Notiser, Lund 1919, p. 271—277.) — Siehe 

 „Allgemeine Pflanzengeographie 1914—1921", Nr. 303. 



307. Gautier, Armand et Clausmann, P. I n f 1 u e n c e des fluoru- 

 res sur la Vegetation. A. Essais p reliminair es en vases 

 de j a r d i n. (Compt. Rend. Acad. Sei. Paris CLXVIII, 1919, p. 976—982.) 



308. Gautier, Armand et Clausmann, P. A c t i o n des fluorures 

 sur 1 a Vegetation. B. Cultures en champ d'experiences. 

 (Compt. Rend. Acad. Sei. Paris CLXIX, 1919, p. 115—122.) 



309. Gessard, C. Sur une eulture pyoeyanique. (Compt. 

 Rend. Acad. Sei. Paris CLXXI, 1920, p. 323—325.) 



310. Gile, P. L. and Carrere, J. O. Absorption o f nutrients 

 as e f f e c t e d b y thenumber o f r o o t s supplied w i t h t h e 

 nutrient. (Journ. Agric. Res. 9, 1917, p. 73—95.) — Summary: „Tests 

 were condueted in water cultures to see wether a plant could absorb a 

 maximum amount of one mineral element which was supplied to only part of 

 the roots if all other essential elements were supplied to all the roots. The 

 absorption of nitrogen with r;ce and com and of phosphorus, potassium, and 

 iron with rice was tested in this way, one-half the roots being maintained 

 in a nutrient Solution lacking one of these elements. Tests were also con- 

 dueted, varying the portion of roots in the complete and incomplete Solutions. 

 — The results show that, under the conditions described, the plant does not 

 absorb a maximum amount of the element, and the fewer the roots supplied 

 witli llie element, the smaller the total amount absorbed. This applies when 

 the total amount of the element supplied is equal to or in excess of the needs 

 of the plant. A curve was plotted showing approximately what portion of the 

 maximum absorption can be expected with any fraction of the roots 

 supplied with the element. With nitrogen and phosphorus the total amount 

 absorbed by plants with half their roots in the complete Solution was 0,76 of 

 that absorbed by plant with all their roots in the complete Solution. The 

 similar figure for potassium or iron was 0,66. Increasing the concentration 

 of the element in question in the complete Solution did not appreciably 

 alter the results. — The amount of the element absorbed per gram of roots 

 increased greatly as the number of roots in the complete Solution was 

 diminished. — The results are explained on the basis of the rate of utilization 



