] 96 TJie Development of the Grain of Wheat 



how ftir the weight of the produce is afifected if the crop is cut 

 while still unripe or after it had experienced a premature and forced 

 ripening. 



The scientific conception which lay behind these opinions proceeded 

 from the observation that grain contained a higher percentage of nitrogen 

 when immature than when ripe, whereupon it was concluded that the 

 migration of the nitrogenous materials took place first, and that during 

 the later stages of the development little besides starch was filled into 

 the grain. Thus grain cut unripe would contain more of the nitrogenous 

 compounds making up the gluten, which is the cliief factor in deter- 

 mining the strength of flour. Furthermore, if grain is rapidly grown 

 and prematurely ripened time would not be given for the complete 

 migration of the starch, and the grain would remain stronger because 

 the protein has been less diluted by starch. 



It has also been supposed that as the nitrogenous compounds of the 

 grain must enter it in a soluble non-protein form, which gradually 

 becomes converted into protein as the ripening process proceeds, 

 another reason for the ' strength ' of certain foreign wheats could be 

 found in the thoroughness with which the conversion into protein 

 had taken place, through the heat of the climates where they were 

 grown. 



Such are, or were, the opinions on the ripening of wheat generally 

 accepted ; their supposed basis in fact did not however prove trust- 

 worthy on experiment. For example, in the experiments of the Home 

 Grown Wheat Committee^ wheat cut in a green state did not yield any 

 stronger flour than the same wheat allowed to become dead ripe ; nor did 

 variations in the date of sowing from October until March affect the 

 strength of the resulting wheat. Moreover, from the numerous trials 

 made by that Committee of the strength of foreign wheats grown in 

 England and, in one case, of an English wheat grown in Hungary, it 

 became evident that the effect of climate in determining the strength 

 of wheat has been exaggerated. Strength turns out to be in the main a 

 characteristic of the variety, besides which climate, soil and manuiing, are 

 only minor factors in the result. In consequence of this conflict of opinion 

 it was decided to make a re-examination in detail of the progressive 

 changes which could be observed in the composition and nature of the 

 wheat grain. Not only was the migration of the materials studied by 

 analysis but the changes in tlie intimate structure of the grain and of 



I Humphries aud Biffen, J. Agri. Sci. 1907, ii. 1. 



