VOLUME LXVIII NUMBER 5 



Reprinted for private circulation from 

 The Botanical Gazette Vol. LXVIII No. 5, November iqiq 



THE 



Botanical Gazette 



UBKAIH 



NEW Y©'« 



NOVEMBER igig botanic 



CHEMICAL CONSTITUENTS OF AMARANTHUS 



RETROFLEXUS 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 254 



M. L. W o o 



(with ELEVEN figures) 



Introduction 



It is a well known fact that weeds retard the development of 



cultural plants. This is due to a number of causes: use of water, 



shading, use of nutrient salts, etc. It has been claimed for various 



' species of Atnaranthus that they not only absorb nitrates to care for 



their nutrient needs, but that they store much nitrogen as nitrate. 



If this be true, this genus has an excellent adaptation to enable it 



to combat cultural plants, for nitrate supply is a common limiting 



factor for crop growth. In order to investigate this statement, to 



locate the place of nitrate storage, and to determine the amount 



of nitrogen used otherwise by this plant, separate analyses were 



made of roots, stems, leaves, and branches of Amaranthus retro- 



flexus at various stages and under various conditions of growth. 



The amount of the several carbohydrates was also determined in 



each analysis, in order to calculate the carbohydrate-nitrogen ratio 



^ which is lately receiving so much attention. A tissue analysis of 



^ the seeds was also made in an endeavor to ascertain more fully the 



y$ chemical constituency of this plant, with the hope of learning 



~h more of the peculiar germinative behavior of these seeds. 



--1 3*3 



