Metabolic Profile Changes and Early Detection of Nitrogen Deficiency in Sweet Corn

In this study, we investigate the nutrient supply of young corn (Zea mays var. rugosa) plants using conventional biological and chemical methods, as well as the N-glycan and metabolic profile of the plant sap using the MALDI-MS. Corn plants with three different nutrient supplies were grown on sandy soil for 45 days after emergence. In treatment 1 (T1), used as a control, the plants did not receive any nutrient supplementation. Plants in treatment 2 (T2) received “ideal” N-, P-, and K-nutrient supplementation in the form of inorganic fertilizers. In treatment 3 (T3), the plants were provided with the ideal amount of P and K, and a reduced amount of N fertilizer. In addition to the amount of biomass of the young plants, macronutrient content (N, P, K, Ca, and Mg) was measured in the dry matter. We examined the amount of 0.01 M CaCl2-soluble N fractions of the experimental soils, and the P, K, Ca, and Mg content of their ammonium lactate (AL)-soluble fractions. We were unable to statistically distinguish between T1, T2, and T3 treatments using conventional methods (in this phenophase). Metabolic profiles in the sap from young plants, captured by MALDI-MS, showed significant differences between the control, “ideal”, and N-deficient treatments. This method may also be suitable for early detection of N-deficient conditions in other plants.