AGRICULTURAL BOTANY. 227 



The soil used was exceiitioiially jioor and the effect of each plant fo(Kl was 

 readily shown. Toward the uialurily of the plants, the portions above ground 

 as well as the roots lost in weight, the reduction being the largest where no 

 nitrogen or fertilizer of any sort had been applied. Oats produced the greatest 

 prt)p()rtion of roots, followed by barley, mustard, and buckwheat in decreasing 

 order. A lack of nitrogen in the soil induced a greater root growtli than a 

 hick of either potash or phosphoric acid. Without potash oats produced 62 

 per cent of the crop resulting from the use of a complete fertilizer. 



The mineral nutrition of plants during germination, C. Schreiber (Rev. 

 Crii. Agron.. n. svr., .) (i:)Oi)), No. 1, pp. l-'i). — According to the author, many 

 physiologists claim that young plants do not take up mineral matter until after 

 the reserve material in the albumen and cotyledons has been used and the 

 first permanent leaves have made their appearance. To determine this, he 

 carried on a series of exi)erinients with a large number of dicotyledonous and 

 other plants the cotyledons of which are epigeous in germination. 



Tlie experiments with radish, colza, white mustard, and spurry a.re described 

 at some length. It appears that plantlets whose cotyledons develop above 

 ground after the germination of the seed are able to take up mineral matter 

 from the soil before the reserve material of the grain is completely used and 

 before the appearance of permanent leaves. 



A study on the disassimilation of plants, N. T. Deleano (Arch. Sci. Biol. 

 [St. Petersb.], li (1909), No. 1-2, pp. 159-172, dgiiis. 6').— In a previous publi- 

 cation ( E. S. R., IS. p. 923), the author in collaboration with others showed 

 that the curve of assimilation and growth of plants ascended rapidly for a 

 time, to be followed by a period of less active increase, and finally by a reduc- 

 tion in the mineral content of the plant largely due to diffusion. This last 

 pliase of the subject has been studied further with StrriuiiKitocijsU.s nigra, 

 comparisons being made with oats. 



As with tlie oats, the maximum of dry and mineral matter was reached at 

 about the time of fruiting, after which there was a gradual reduction corre- 

 sponding with a cessation of protoplasmic development. 



A study was also made of the soluble and insoluble nitrogen in the fungus 

 after fruiting, and the author claims that these nitrogenous products result 

 from the decomposition of the complex albuminoids immediately after fructifi- 

 cation. 



Studies on chlorophyll, .M. Tsvett (Biochem. Ztschr., 10 (1908), No. 4-S, 

 pp. -'iOJf-Ji2D). — A study was made of some of the chlorophyll derivatives, 

 lihaeophytin, chlorophyllan, pliylloxanthin, and crystallized chlorophylls, and a 

 (liagranmiatic system is presented for the classification of the so-called chloro- 

 phyll derivatives. 



The photodynamic work of chlorophyll and its relation to photosynthesis 

 in plants, W. Hausmann (Biocliciit. Ztschr., 16 {1909), No. .',-5, pp. 2'J',^.U2) .— 

 According to the author, alcoholic extracts of leaves have a pliotodynamic 

 effect on the red corpuscles of the blood as well as upon Paramecium. The 

 photodynamic work of plant extracts containing chlorophyll and of pure 

 clilorophyl! takes place in the same portions of the spectrum in which the 

 highest assimilatory activity of the plants is shown. He states that it is 

 jirobable that chlorophyll in plants acts as a sort of photodynamic substance 

 which incites photosynthesis, and the present state of information seems to 

 point to an intimate connection between photosynthesis and the photiMlynamic 

 work of plants. Phylloporphyrin and h:ematoporphyrin have similar photo- 

 dynamic activities. The close relationship between tlie coloring material of 

 1)1(K»(1 and chlorophyll is further shown by the similar photodynamic work of 

 their derivatives. 



