FIELD CROPS. 



<)43 



FIELD CROPS. 



A report of progress of investigations in the chemistry of wheat, 

 G. L. Teller (Arkansas Bui. 52, pp. 53-81). — This is a continuation of 

 the authors investigation (E. S. R., 8, p. 854). He refers to bis conten- 

 tion that the wheat proteid designated by Osborne and V oorhees as a pro- 

 teose is gliadiu, and offers " further proof that the conclusion is correct." 



jMost of the bulletin is devoted to a study of the changes in wheat 

 from the time the grain began to set until it was overripe. A half 

 acre of wheat which gave promise of being very uniform was used for 

 the investigations, but as the wheat matured the held was found to be 

 less uniform than expected. Beginning May 22, when the wheat was 

 past blooming and the grain was set, cuttings were made daily at the 

 same hour on 42 successive days, about one half of each cutting being 

 dried on the straw, and the heads being cut from the other half and 

 dried separately. The wheat from each cutting was thrashed and 

 cleaned, "that used for analysis being hand picked to free it from all 

 foreign matter."' The number of kernels in 10 gin. of each sample was 

 determined. This shows a quite regular decrease from 3,583 kernels 

 for the first cutting to 246 for the last cutting. 



The quantitative method used for separating the proteids was that 

 described in Bulletin 42 of the station (E. S. R., 8, p. 854), except that 

 in the extraction of the gliadin alcohol of 0.9 sp. gr. (about 58 per cent 

 by weight) was used instead of 75 per cent alcohol, as formerly recom- 

 mended. The nitrogen compounds were determined in each of the 42 

 samples of wheat ripened on the straw; the nitrogen was determined 

 in the grain of the heads cut from the straw for the first 36 days, and 

 a complete determination of the nitrogen compounds of the third sam- 

 ple of this series was made. These data are tabulated on the basis of 

 dry matter and of total nitrogen, and the differences in composition 

 where the heads were cut from the straw and the grain cured on the 

 straw are given. A summary of the nitrogen compounds for groups 

 of 3 days is given in the following table: 



Nitrogenous compounds in wheat at different stages of maturity, in percentages of the 



total nitrogen. 



Period. 



Stage of maturity 



9 

 10 

 11 

 a(ll) 

 12 

 13 

 14 



A little past bloom; grain set 



Berries one-half to full length of ripe grain 



Grain coming in milk; lower leaves dying 



Grain well in milk 



Heads and kernels well developed; thin dough 



Grain in dough 



Grain in stiff dough ; straw becoming yellow at butt. 



Straw much yellowed but still decidedly green 



Straw still a little green 



Wheat fit to cut; berry nearly dry 



Grain overripe '. 



do 



do 



do 



do 



Edestin 

 Gliadin Glutenin andleuco- Amid 



nitrogen, nitrogen, i sin nitro- nitrogen, 

 gen. 



28.4 

 34.7 

 39.9 

 41.9 

 43.3 

 45,6 

 48 5 

 51). 

 53. 5 

 53.3 

 51.9 

 (52. 9) 

 53. 5 

 52.4 

 53.0 



44.2 

 43.1 

 37.8 

 36.2 

 85. 7 

 35.6 

 35.8 

 35 9 

 32.7 

 31.5 

 33.2 

 (32.4) 

 31.1 

 32.3 

 31.9 



11.9 

 13.7 

 15.1 

 15.2 

 14.7 

 13.9 

 11.4 

 10.3 



10.4 

 11.8 

 11.6 

 (11.5) 

 11.5 

 11.1 

 11.3 



15.5 

 8.5 

 7.2 

 6.7 

 0.3 

 4.9 

 4.3 

 3.8 

 3.4 

 3.4 

 3.3 

 (3.2) 

 3.9 

 4.2 

 3.8 



a Figures in parentheses give average of group, omitting one sample which was irregular. 



18562— No. 10 4 



