1919] WOO— A MARA. \ Til US 321 



phospholipid, etc., and all of the nitrates of the leaves seem to be 

 used up in these syntheses. The nitrates are carried from the roots 

 to other parts of the plants as fast as they are taken up from the 

 soil. There may be as high a concentration of nitrates in the roots 

 as in the soil (29 parts per million). This low concentration cannot 

 be estimated by this method and would therefore be missed. 



The stem and branches are the primary nitrate storage organs. 

 The nitrate content rises as high as 8.58 per cent in the stem and 

 12.5 per cent in the branches during the early seed formation 

 period. This high content is shown still more clearly by the ratio 

 of nitrate nitrogen to the total nitrogen. This is 32 .8 per cent for 

 the roots, 51.85 per cent for the stems, 56.4 per cent for the 

 branches, but only 1.25 per cent in the leaves. Curves showing 

 this ratio in these organs at different stages are given in fig. 2. 

 This large supply of nitrates in the stem and branches may be 

 drawn upon heavily for further growth and seed production, 

 although the supply seems more than adequate for these uses. 

 There is also no reason for thinking that nitrate absorption ceases 

 at this time. The extent to which this storage of nitrate is drawn 

 upon by later development could be ascertained by the analysis 

 of a set of samples taken late in the fall when seed formation and 

 growth were complete. It is to be regretted that circumstances 

 made such an analysis impossible for this paper. 



It is worthy of note that the nitrate storage organs are the ones 

 that made the most rapid growth in length, weight, and volume. 

 The stem which rose from 8 inches on June 20 to 20 inches on July 8 

 at the same time increased in nitrate content from 1.71 to 8.58 

 per cent on dry weight basis. In addition to the stem there are 

 numerous side branches which elongated from 0.1 to 14 inches in 

 18 days, making nearly 1 inch in 24 hours. At the same time there 

 was an increase in percentage of nitrates per gram of dry matter 

 from 1. 7 1 on June 20 to 12.50 per cent on July 8. The rate of 

 nitrate intake per gram per hour seems to follow a geometrical 

 progression in each individual plant. 



It appears that Amaranthus may be a very considerable factor 

 in depleting soils of their nitrates. Also in case the weeds are 

 burned the nitrogen sto/ed is permanently lost from the soil. It 



