02423nam a2200253Ia 4500 MX-MdCICY 20260521091429.0 CICY B-14689 Beneficial Role of Exogenous Spermidine on Nitrogen Metabolism in Tomato Seedlings Exposed to Saline-alkaline Stress J. Amer. Soc. Hort. Sci., 138, p.38-49, 2013 We studied the effects of exogenous spermidine (Spd)on plant growth and nitrogen metabolism in two cultivars of tomato (Solanum lycopersicum)that have differential sensitivity to mixed salinity-alkalinity stress: 'Jinpeng Chaoguan' (salt-tolerant)and 'Zhongza No. 9' (salt-sensitive). Seedling growth of both tomato cultivars was inhibited by salinity-alkalinity stress, but Spd treatment alleviated the growth reduction to some extent, especially in 'Zhongza No. 9'. Exogenous Spd may help reduce stress-induced increases in free amino acids, ammonium (NH4 +)contents, and NADH-dependent glutamate dehydrogenase (NADH-GDH)activities; depress stress-induced decreases in soluble protein and nitrate content; and depress nitrate reductase, nitrite reductase, glutamine synthetase (GS), NADH-dependent glutamate synthase (NADH-GOGAT), glutamate oxaloacetate transaminase (GOT), and glutamate pyruvate transaminase (GPT)activities, especially for 'Zhongza No. 9'. Based on our results, we suggest that exogenous Spd promotes the assimilation of excess toxic NH4 + by coordinating and strengthening the synergistic action of NADH-GDH, GS/NADH-GOGAT, and transamination pathways, all during saline-alkaline stress. Subsequently, NH4 + and its related enzymes (GDH, GS, GOGAT, GOT, and GPT), in vivo, are maintained in a proper and balanced state to enable mitigation of stress-resulted damages. These results suggest that exogenous Spd treatment can relieve nitrogen metabolic disturbances caused by salinity-alkalinity stress and eventually promote plant growth. AMMONIUM ASSIMILATION GLUTAMATE DEHYDROGENASE GLUTAMINE SYNTHETASE GLUTAMATE SYNTHASE TRANSAMINATION Zhang, Y. Shy, Y. Hu, X-H. https://drive.google.com/file/d/10HSsV8gO40YBWho8mmQzd_LyUQJ2vMDw/view?usp=drivesdk Para ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx Loc REF1 250602s9999 xx |||||s2 |||| ||und|d 24813 24813 0 0 Loc 0 0 F1 CICY CICY RE 2025-06-25 0 B-14689 2025-06-25 15:39:46 2025-06-25 REF1