No. 1, July, 1920] PHYSIOLOGY 215 



1424. EOAQLAND, I>. R. Relation of the concentration and reaction of th^r nutrient medium 

 to the growth and absorption of the plant. Jour. A I 18: . 117 / g, ! .'. 1919.— 

 This is an attempt to correlate the result of recent tnethodi of invi ion in plant nutri- 

 tion with the present knov Ledge of i oil b dutions. Beldi barley was grown in nutrient solu- 

 tions arjd in sand irrigated with nutrient solutions. Special < Ideficien 

 of nutrients. I where the effects of acidity were to be determined, a neutral solution of 

 nutrient salts was used which varied in composition and tcital concentration. In some 



the ' centration of the nutrient solution was reduced after tl in imitation of 



cert; n seasonal conditions observed with water extract The result 



Optimal concentration of the nutrient Bolution to be not over 0.6, and 0.1, 



atmosphere. With the more concentrated solutions, nitrogen and pi 

 in the tops of the plants, while it appeared that insoluble phosphat im 



were deposited in the roots. The critical period of absorption of nutri I to f -tl I 



between the third and tenth weeks of growth. 1 ive, and appari I rp- 



tion occurred thereafter from the more concentrated solution-;. Reduction of of 



nutrient salts after the tenth week reduced the final yield of straw, bul not It 



appeared that electrolytes might be returned to the nutrii under 



conditions' of high concentration of the nutrient solution or of low light in The 



plant sap was found to have a uniform acidity of l'„ 6.1. Acid reaction of the nutrient solu- 

 tion (P H 5.0-5.5) was favorable, and attended by excessive absorption of P< >< by the plant 

 The latter absorb the anion faster than the cation from NaNOi, but the excret ' >i 



regulates the alkalinity of the nutrient solution. Plants transferred from solutions to 

 lost Ca and PO4. The author urges consideration of variability in plants in interpreting the 

 yields of culture experiments. — A bibliography of 56 titles is appended. — 11'. K. Totlingham. 



1425. Pfeiffer, Th., W. Simmermacher, and A. Rippel (in collaboration with Frl. II. 

 Friske and Frl. Ch. Pfotenhauer). Der Gehalt der Haferpflanzen an Stickstoff. Phos- 

 phorsaure und kali unter berschiedenen Bedingungen und seine Beziehungen zu der durch 

 eine Nahrstoffzufuhr bedingten Ertragserhohung. [The nitrogen, phosphoric acid, and potas- 

 sium content of the oat plant under different conditions and their relations to the increased 

 yield resulting from addition of nutrients.] Jour. Landw. 67: 1-57. 6 fig., 15 tables. 1919. — 

 Investigations are reported having to do with the nutrient content of plants as a measure of 

 the fertilizer needs of the soil. Oat plants were grown in receptacles under different condi- 

 tions as regards nutrients, water, and light. The results obtained serve as the basis for var- 

 ious calculations in which the formula of Mitscherlich [log (A— y) = k— c.x] enters in the con- 

 struction of yield-curves. — The authors believe that the plant-analysis may in extreme cases 

 serve as a measure of the fertilizer needs of the soil, and that they have establie aeoret- 

 ical groundwork for the existing relation with respect to nitrogen, phosphoru crimps 

 potassium. — C. E. Leighly. 



1426. Will am an, J. J. Mineral absorption in spinach. [Rev. of: True, R. H., O. F. 

 Black, and J. W. Kelly. Ash absorption by spinach from concentrated soil solutions. Jour. 

 Agric. Res. 16: 15-25. 1919 (See Bot. Absts. 2, Entry 1118).] Bot Gaz. 68: 69-70. 1919. 



PHOTOSYNTHESIS 



1427. Anonymous. Nature's factories for sugar and starch. Sci. Amer. Supplem. 87: 

 223. 1919. — Photosynthesis discussed in a popular style. — Chas. H. Otis. 



1428. Boysen-Jensen, P. Studies on the production of matter in light and shadow plants. 

 Bot. Tidsskr. 36: 219-259. Fig. 1-7. 191S.— In determining the amount of organic material 

 or the increase in dry weight produced per unit time for Sinapis alba flight loving plant) 

 and Oxalis acetosella (shade loving plant), Boysen-Jensen has measured the | 



intensity. To measure the amount of C0 2 used in photosynthesis and that produced during 



respiration the absorption method with a few modifications has boon employed. 1 



light intensity rhodamin B paper has been used. This, however, does not give other than com- 



