1917) AGRICULTURAL BOTANY. 431 



The liest j^errnination of Albizzla seed was securerl when the seed was soaked 

 for at least three hours in water at a temperatui'e of about 60° C. Mimosa seed 

 gave the best results when soaked in water of from 60 to 70°, and Pithecolobium 

 seed when the temperature of the water was from 70 to 75°. Soaking in 

 warm water was disadvantageous to Crotalaria seed and soaking in cold water 

 was not of much advantage. 



The physiology and technique of forcing growth in woody plants, F. La 

 Maeca (Stas. Sper. Agr. Ital. 48 (1915), No. 10-11, pp. 772-782).— Tests as de- 

 tailed with various woody plants in regard to the effects of removing bud scales, 

 puncturing the bud with a fine needle, injecting water or compounds of copper, 

 iron, nickel, etc., have led to the conclusion that the forcing effects observed are 

 due almost wholly to the disturbance consequent upon wounding or to the conse- 

 quent release from pressure in the bud. 



Injury to vegetation resulting from climatic conditions, G. E. Stone 

 (Jour. N. y. Bot. Oard., 17 (1916), No. 202, pp. 173-179; V. S. Mo. Weather 

 Rev., 44 (1916), No. 10, pp. 569, 570). — The general conditions which result in 

 winter injury to plants are briefly stated, and more complete accounts are given 

 of the character and causes of frost cracks, sim scald, sim scorch, and bronzing. 



The formation of parenchyma wood following winter injury to the cam- 

 bium, A, J, Mix (Phytopathology, 6 (1916), No. 3, pp. 279-283, figs. cJ).— The 

 author describes the formation of parenchyma following winter injury to apple 

 trees. 



Effect of sodium salts in water cultures on the absorption of plant food by 

 wheat seedlings, J. F. Breazeai^ (U. S. Dept. Agr., Jour. Agr. Research, 7 

 (1916), No. 9, pp. 407-416, figs. 8). — The results are given of experiments under- 

 taken to determine the extent to which the presence of the various sodium 

 salts commonly found in alkali soils affects the absorption of plant food ele- 

 ments by wheat seedlings. Sodium chlorid, sulphate, and carbonate, in con- 

 centrations ranging from 50 to 1,000 parts per million, were employed in 

 connection with a standard nutrient solution, and wheat plants grown on 

 floating disks were used to test the effects of the different salts. 



All of the sodium salts tested, when added to the nutrient solutions, even 

 in the highest concentrations mentioned, did not measurably affect the nitro- 

 gen absorbed from the culture solutions, but sodium chlorid decreased the 

 absorption of potash slightly, though it did not affect that of phosphoric acid. 

 Sodium sulphate In concentrations of 1,000 parts per million depressed the 

 absorption of potash and phosphoric acid to approximately 70 per cent of that 

 of the control cultures. Sodium carbonate in the same concentration reduced 

 the absorption of potash to 20 per cent of the control and that of phosphoric 

 acid to 30 per cent. The depressing effect of sodium carbonate was also ob- 

 served in concentrations as low as 100 parts per million. 



The relative effect of sodium sulphate and sodium chlorid in depressing the 

 absorption of potash is said to be directioually the same as the relative 

 hydrolysis resulting from the reaction of the two salts with the calcium car- 

 bonate present in the culture solution. This is believed to suggest that the 

 observed effects in the case of sodium sulphate and sodium chlorid may be due 

 in part to the accumulative action of the slight amounts of sodium carbonate 

 formed in this reaction. 



Assimilation of iron by rice from certain nutrient solutions, P. L. Gile 

 and J. O. Caerebo (U. S. Dept. Agr., Jour. Agr. Research, 7 (1916), No. 12, pp. 

 503-528). — The results are given of a series of investigations carried on at the 

 Porto Rico Experiment Station to determine whether the reaction of soils has 

 any effect on the assimilation of iron by rice. Rice was grown in acid, neutral, 



