246 



NUTS TURNIP 



The following shows the composition of the edible portion of 

 several varieties : 



CLASS 2. ROOT CROPS. 



In these crops, the valuable portion is the large store of organic 

 matter which the plants produce during the first year, either in 

 their underground stem or in enlargements (tubers) on their roots, 

 this reserve being intended to serve as a source of material from 

 which, in the second year, the flowering stem, flower and seed may be 

 formed. 



The chief English crops of this type are : the turnip (Brassica 

 Napus, Linn, or Brassica rapa rapifera, Metzger), the swede (Brassica 

 campestris rutabaga, Linn, or Brassica Napus esculenta, D.C.), the 

 mangold or beet (Beta vulgaris), the potato (Solatium tuberosum), the 

 carrot (Daucus carota), the parsnip (Pastinaca sativa), and the radish 

 (Baphanus sativa). Other crops, growing in warmer countries, 

 which may be mentioned here are the sweet potato (Ipomma batatas 

 or Batata edulis) and the Jerusalem artichoke (Helianthus tuberosus). 



The Turnip grows best in cool, damp climates ; in hot, dry coun- 

 tries the roots become woody and fibrous. 

 The average composition of the root is 



Water. 

 90-67 



Protein. 

 1-12 



Fat. 

 0-24 



Sugar. 

 2-55 



Other N-free extract. 

 3-55 



Fibre. 

 Ml 



Ash. 

 0-76 



but great variations are shown. The important factors affecting the 

 composition, are, in order of importance, season, variety, size of root, 

 district and soil. 



But even in the same variety, grown apparently under the same 

 conditions and with roots of approximately the same size, variations 

 in composition in individual roots are often found, especially in the 

 amount of sugar present. 



The "protein," (i.e., total nitrogen x 6'25), of turnips includes from 

 27 to 50 per cent of the total nitrogen in forms other than proteids, 

 viz., as amino-compounds and nitrates. 



The sugars present are chiefly glucose and sucrose, the former 



