NUTRITION STUDIES WITH CORN

Abstract

Carbohydrate and N fraction relationships were interpreted statistically in an attempt to establish correlations between the concs. of the various nutrient ions in the substrate and the status of N metabolism with corn tissue, grown in sand culture using a variable ion-proportion series. All calculations were based on fresh weight data. Within the limits used, PO4= and S04= concs. had no demonstrable correlation with N metabolism. Increasingly high NO3 concs. in the substrate increased the content of nitrate, ammonium, basic-free a-amino, amide, basic, and protein N in the tissues. Increasingly high concs. of NO3'' in the substrate decreased the tissue content of reducing sugars, starch and dextrins, and hemicelluloses. Increasingly high concs. of Ca++ in the substrate slightly decreased the soluble N fractions, slightly increased the protein N content, and increased the complex reserve carbohydrate content of the tissues. Correlations between Ca++ in the substrate conc. and the reducing sugar and sucrose content of the tissues were not significant. Increasingly high Mg++ concs. within the limits used had no appreciable effect upon carbohydrate-N relationships. Increasingly high K+ concs. in the substrate had little effect on the protein or basic N content of the tissues but decreased the tissue content of all other soluble N fractions. Increasingly high K+ concs. in the substrate decreased the content of reducing sugars in the tissue, but had no appreciable effect upon sucrose, starch and dextrin, or hemi-cellulose content of the tissue.[long dash]K may be essential to the processes by which energy utilized in N metabolism is released from the simple sugars.