[Effect of enhanced ammonium nutrition on photosynthesis and nitrate reductase and glutamine synthetase activities of winter wheat].

A controlled hydroponics experiment was conducted to investigate the effects of three NH4+/NO3- ratios (0/100, 50/50 and 100/0) on the photosynthesis and the key nitrogen metabolism enzymes of three wheat cultivars with different sensitivity to enhanced ammonium nutrition (EAN). Compared with NO3- alone, EAN significantly increased the leaf chlorophyll content, net photosynthetic rate, and soluble sugar content. It also significantly increased the soluble protein content in leaves and roots and the nitrate reductase activity in leaves, but had no significant effect on Glutamine synthetase (GS) activity. EAN increased the soluble sugar content in leaves, and correspondingly, enhanced the net photosynthetic rate and maintained a higher soluble sugar/protein in leaves and roots, which was favorable to the nitrogen assimilation and plant growth.