The effect of nitrogen forms on the growth and quality of Pinellia ternata

To explore the effects of different forms of nitrogen on the growth and quality of Pinellia ternata, and to provide the basis for nitrogen fertilizer application for high quality and high yield cultivation of P. ternata. A single-factor randomized block design was used. Three forms of nitrogen of Ammonium nitrogen, nitrate nitrogen, and amide nitrogen were applied at rates of 5, 10, and 15 g·m⁻². The agronomic traits, yield and quality indexes of P. ternata plants were determined with no nitrogen application as control. The results showed that the nitrate nitrogen treatment 5g·m⁻² produced the largest bulbil and mother stem diameters and maximum fresh weights. Maximum tuber yield was achieved with ammonium nitrogen at 10g·m⁻². Phytochemical analysis demonstrated that ammonium nitrogen at 15 g·m⁻² significantly enhanced hypoxanthine and adenosine concentrations, while amide nitrogen application 10 g·m⁻² optimized uridine content. Notably, nitrate nitrogen at 15 g·m⁻² simultaneously maximized guanosine levels and water-soluble protein content. A multi-criteria evaluation integrating agronomic traits, yield, and quality indices through an entropy-weighted TOPSIS model revealed significant treatment efficacy differences. The ammonium nitrogen treatment at 15g·m⁻² demonstrated optimal performance, while the 10 g·m⁻² amide nitrogen application exhibited the lowest efficacy. This systematic analysis establishes that ammonium nitrogen application at 15 g·m⁻² synergistically enhances both biomass production and phytochemical quality in P. ternata cultivation, particularly through increased accumulation of hypoxanthine and adenosine compared to baseline levels.