BOOKS AND CURRENT LITERATURE 



Absorption of Carbohydrates by Green Plants. — The fact 

 that phanerogams are capable of absorbing by means of their roots a 

 considerable number of organic substances and assimilating them, 

 is not a matter of general knowledge among botanists. A recent 

 memoir by Knudson' brings together the earlier evidence in support 

 of this fact and contributes in addition, a considerable body of data 

 in substantiation of it. Special emphasis is given to certain phases 

 of the problem, namely, the comparative ease of assimilabilitj'' of the 

 several sugars employed and the influence of varying concentration on 

 growth and respiration. Several species of plants including corn, 

 Canada field pea, radish, cabbage, vetch, wheat, timothy, and sweet 

 clover were employed. The seed were germinated and grown for a 

 period of thirtj^ daj^s in tubes containing agar to which a nutrient 

 solution and either glucose, fructose, maltose, or lactose were added. 

 The dry weight of roots and tops was used in the determination of the 

 amount of growth. 



It was found that not all of the species were able to utilize the same 

 sugar equally well. It was further noted that a certain sugar gave the 

 best growth when the plant was kept in the light while a different sugar 

 exerted the most beneficial effect in the darkness. 



Respiration was manifestly influenced as early as the fifth day of 

 the experiment. 



Concentrations of galactose as low as 0.0125% were injurious to 

 vetch, Canada field pea, corn and wheat. This toxicity could be 

 antidoted because of an antagonistic action which was found to exist 

 between galactose and glucose when certain concentrations were em- 

 ploA^ed. — Frederick A. Wolf. 



Root Hairs. -rRoberts, in a recent contribution from the Hull Bo- 

 tanical Laboratory ,2 reports some results obtained in her study of root 

 hairs. She finds that the ratio between the length of cortical and epi- 



^ Knudson, Lewis, Influence of certain carbohydrates on green plants. Cornell 

 Agr. Exp. Sta. Mem. 9, 9-75, fig. 11. 1916. 



-Roberts, Edith Adelaide, The epidermal cells of roots. Bot. Gaz. 62, 488-506. 

 1916. 



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