222 EXPERIMENT STATION BECORD. [Vol. 37 



A list of 27 references to literature bearing on the subject is appended to- 

 gether with an author index. 



Glandular hairs on roots, G. Habeblanot: {Sitzber. K. Prouss. Aknd. Wiss., 

 1915, XII, pp. 222-226, figs. 6). — The author gives a preliminary report of the 

 occurrence, structure, etc., of multicellular glandular hairs. These were dis- 

 covered to exist in greater or less abundance on nearly all the rootlets from 

 2 to 8 mm. in length, springing, with adventitious buds, from marginal leaf 

 notches of Bryophyllum calycimim kept in a glass in the laboratory. The vari- 

 ous forms are described and discussed. 



Absorption of nutrients as affected by the number of roots supplied with 

 the nutrient, P. L. Gile and J. O. Carrero {U. 8. Dept. Agr., Jour. Agr. Re- 

 search, 9 {1917), No. 3, pp. 7S-95, figs. 2). — In a contribution from the Porto 

 Rico Experiment Station, the authors give a report on tests conducted in water 

 cultures to see whether 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 plants were grown with 

 their roots divided between two flasks, one of which contained a complete 

 nutrient solution and the other a nutrient solution lacking one element, and 

 the absorption of nitrogen with rice and corn and of phosphorus, potassium, and 

 iron with rice was tested. 



The result.s show that, under the conditions of the experiments, the plant 

 is not able to absorb a maximum amount of the element, and the fewer the 

 number of roots supplied with the element, the smaller the amount absorbed. 

 This is found to apply when the total amount of the element supplied is equal 

 to or in excess of the needs of the plant. With nitrogen and phosphorus, the 

 total amount of the element absorbed by plants with half their roots in the com- 

 plete solution was equal to 0.76 of that absorbed by plants with all their roots 

 in a complete solution. The similar figure for potassium and iron was 0.66. 

 An increase in concentration of the element in question in the complete solution 

 did not appreciably alter the re.sults. The amount of the element absorbed per 

 gram of roots increasetl greatly as the number of roots in the complete solution 

 was diminished. 



Attention is called to the bearing of these results on the method of applying 

 fertilizers. 



The excretion of acids by roots, A. R. Haas (Proc. Nat. Acad. Set., 2 {1916), 

 No. 10, pp. 561-666). — Controlled experiments with sweet corn seo<llings grown 

 in water culture indicated that no acids other than carbon dioxid were excreted 

 by the roots. The increase in the alkalinity shown by one culture in quartz in 

 seven days is thought to indicate the presence of .some dead cells not visible. 

 Distilled water into which only the roots of wheat seedlings extended showed 

 a very slight increase in alkalinity when the roots had decayed, but when the 

 screen, seeds, and roots were in water a slightly greater increase in alkalinity 

 was noticed. 



Leaf epidermis and light perception, G. Haberlandt (Sitzber. K. Preuss. 

 Akad. Wiss., 1916, XXXII, pp. 672-687).— TMh is mainly a discussion of con- 

 tributions by other investigators as bearing upon the author's theory regarding 

 the sensitivity to light of foliar organs. According to this view, structural 

 peculiarities in the cells near the upper side of the leaf cau.se differences in 

 illumination, and thus serve as a means of detecting the direction of the 

 incidental light ray. 



The chemical organization of the assimilatory apparatus, R. Wuxstatteb 

 and A, Stoli, {Sit::hcr. K. Preuss. Akad. Wiss., 1915, XX, pp. S22S46. fig. 1).— 

 Several series of tests with flowers having foliage of different colors are de- 



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