8 TKANSLOCATIOJT OF PLANT FOOD IN WHEAT SEEDLINGS. 



nuclein, sugars, fiber, and pentosans, and a decrease of fat and pro- 

 tein, while the total nitrogen and ash remained unchanged. 



De Chalmot,^ in his work on cereals, came to the conclusion that 

 pentosans were produced from the sugars, but were not a result of 

 direct assimilation; that the process of their formation did not con- 

 tinue after the death of the plant, and that the pentosans in the 

 seeds were present as reserve material. 



Deleano ^ made a study of the castor-oil bean, with special ref- 

 erence to the behavior of the fat, and found that the fat content 

 remained practically constant up to the eighth day after germination, 

 after which, from the eighth to the fifteenth day, the decrease was 

 very rapid, falling from 17 grams per 100 plants to about 2 grams 

 without at the same time causing any appreciable loss in dry weight. 

 Coincident with the decrease in fat there was noted a rapid increase 

 in water soluble organic substance. 



Andre,^ in a recent stud}^ of the changes taking place in bulbous 

 plants from the planting of the bulb until the formation of the seed, 

 showed that during the first month the dry weight of the bulb 

 decreased, due to the fact that the aerial portion of the plant feeds 

 on it, but later the bulb increases in weight, omng to the assimi- 

 lative processes of the aerial portion and the subsequent storage of 

 organic material. During the first month the increase in the ash 

 content was found to be due almost entirely to the absorption of 

 magnesium, calcium, and silicon, the nitrogen and phosphorus hav- 

 ing decreased 40 and 17 per cent, respectively. At the end of the first 

 month the aerial portion weighed t^\"ice as much as the original 

 bulb, most of the nitrogen and phosphorus having been absorbed 

 from the soil and not drawn from the reserve already present in 

 the bulb. During the latter stages of growth, toward maturation, 

 the plant used the food stored in the stem for the formation of its 

 seed. 



METHOD OF GEOWING THE SEEDLINGS. 



As it was found (see p. 10) tliat seeds upon being steeped or soaked 

 excrete quite an amount of nutrient salts, the following method of 

 growing the seedlings was adopted: After the seeds had soaked 

 for several hours the water was drained off and they were spread 

 over a perforated aluminum disk, such as is used in the Bureau of 

 Soils, which consists of a modification of that employed by De 

 Chalmot * in 1894. The disk was then placed in a shallow pan, so 

 that the seeds came in contact with, but were not submerged by, the 

 water, which was specially distilled and treated mth carbon black, 

 so as to prevent any toxic action on the seedlings. The water was 

 changed frequentl3^ 



1 Amer. Chem. J., 1894, 16 : 218, 589. s Bull. soe. chim. Par., 1910 (4. ser.), 7 : 865, 927. 



2 Centrbl. Bakteriol. Parasit. 1909, 24 (2): 140. < Loe. cit. 



