Hydroponic culturing upregulates sucrose and glutamine metabolism by enhancing their utilization via intermediates of aerobic pathway in wheat

Abstract

Two wheat genotypes were grown in hydroponic culture, containing 4 mM KNO 3 , NH 4 Cl and NH 4 NO 3 . Activities of N metabolizing enzymes, aminotransferases, carbohydrate and TCA cycle enzymes were analyzed along with protein, amino acid, N, sugar content and growth parameters in shoot and root. After 12 days, the size of shoot and root system decreased significantly when plants were supplied with NH 4 Cl as exclusive N source. Under NH 4 NO 3 growth parameters, N and carbon metabolism were elevated as compared to NH 4 Cl but less than KNO 3 source indicating inhibition of NH 4 + toxicity by NO 3 -uptake. Our results suggested that GDH, aminotransferases and PEPC play an important role in ammonium detoxification by its incorporation into amino acids. Thus, the morphologic differences among plants growing in NH 4 + or NO 3 -nutrition confirm the hypothesis that N source determines the growth habit of plant in wheat by modulating the endogenous levels of protein and sugar content.

Molecular characteristics of humic substances from different origins and their effects on growth and metabolism of Pinus laricio callus

“…The stimulation of respiration during nitrogen uptake has been ascribed to an initial activation of PEPC, leading to an increased production of citric acid cycle carbon skeletons that is required for ammonium assimilation [20]. We found that PEPC activity was stimulated, as compared to control, by all humic and fulvic acids, even though it was a function of the molecular composition of humic extracts.…”