310 SYMBIOTIC NITROGEN FIXATION 



TABLE IV. TOTAL NITROGEN IN LUPINES: RESULTS OBTAINED BY 



KNISELY. (EXPRESSED IN PERCENTAGE ON DRY BASIS). 



Period. Leaves. Pods. Stems. Roots. Nodules. 



Full bloom . . 4.02 3.07 1.15 0.92 5.17 



Pods well formed . . 3.70 3.38 0.88 0.83 3.29 



Pods very large . . 3.41 3.68 0.90 0.66 3.70 



"Schulze and Barbieri examined lupine and soybean seeds and 

 seedlings for nitrogen and obtained the results shown in Table V. 



TABLE V. NITROGEN IN LUPINE AND SOYBEAN SEEDS AND SEEDLINGS: 



RESULTS OBTAINED BY SCHULZE AND BARBIERI (EXPRESSED 



IN PERCENTAGE ON DRY BASIS). 



Total P.T.A. Filtrates 



Material. nitrogen. Protein. nitrogen. from P.T.A. 



Lupine seeds .... 8.63 8.17 0.24 0.22 



Soybeans 6.73 6.32 0.13 0.28 



Lupine dark seedlings, 



eleven to twelve days old 10.64 3.40 1.60 5.64 



Lupine dark seedlings 



twelve days old . . 10.51 2.33 2.17 6.01 



Soybean seedlings fifteen 



days old .... 7.42 3.86 0.56 3.00 



"They also found a large amount of asparagin in both the lupine 

 and the soybean seedlings. 



"Schulze has made a careful study of the compounds in plants, 

 and has formulated the hypothesis that the same decomposition 

 products arise from protein in the plant as outside it, but that in the 

 plant the compounds are further altered, thereby affecting in varying 

 degree the individual products of the hydrolytic decomposition. 

 A comparison of the analyses of pea seedlings one week old and* those 

 three weeks old show the following differences: 



Leucin. Tyrosin. Arginin. Asparagin. 



1 week .... Abundant Little Present Absent. 



3 weeks .... Much less Absent Almost absent Very abundant. 



Arginin and amido-acids were shown to be present in the lupine 

 cotyledons, but asparagin was absent, although the latter substance 

 was found in the stem of the seedling. It has been suggested that 

 the occurrence of asparagin is associated with the disappearance 

 of amido-acids and not of protein. Phenylalanin, tyrosine, and 

 tryptophane have been reported in the white lupine (Lupinus alba), 

 tyrosin and tryptophane in vetch (Vicia sativa), and tryptophane 

 in the garden pea (Pisum sativum). 



"Smith and Robinson found 4.19 per cent, of nitrogen in soybean 

 nodules and 3.90 per cent, in cowpea nodules. They observed that 

 inoculation increased the protein content of soybean plants without 

 increasing the yield of beans. This has been noted by other 

 experimenters. 



