Growth and NO3 - accumulation in hydroponic lettuce with nitrate/ammonium ratios in two cultivation seasons [Crecimiento y acumulación de NO3 - en lechuga hidropónica con relaciones nitrato/amonio en dos estaciones de cultivo] Article uri icon

abstract

  • Lettuce (Lactuca sativa L.) is a leafy vegetable that generates important economic income in Mexico; however, high levels of nitrates (NO3 -) can cause health problems because they generate carcinogenic compounds. An alternative to reduce the NO3 - in leaves is replacing it with ammonium (NH4 %2b), which could benefit human health by lowering intake of NO3 -. The objective of this study was to evaluate the growth and accumulation of NO3 - in lettuce with different ratios of NO3 -/NH4 %2b in the nutrient solution in two growing seasons. The lettuces were grown in a floating root hydroponic system. The experimental design was completely randomized, under a 4 × 2 factorial arrangement, four ratios of NO3 -/NH4 %2b (100/0, 80/20, 65/35 and 50/50) and two seasons (Summer and Autumn), with a total of 8 treatments. The evaluated traits were dry weight of roots (DWR), of leaves (DWL) and total (DWT), leaf area (LA) and NO3 - concentration in petiole. No significant differences were found between seasons in DWL, DWT and LA. In Autumn DWR increased 11 %25 compared to that of Summer. In Summer the NO3 - content in petioles increased by 55 %25 compared to that of Autumn. The 100/0 ratio increased 25 %25 DWL, DW and LA, and 15 %25 NO3 -in petiole. During the Summer, there was an increase of 4 %25 in DWL, DWT and LA by using the 100/0 ratio. When NH4 %2b was used in the 65/35 and 50/50 ratios, growth was reduced by 25 %25 and NO3 - accumulation in petiole by 15 %25. In the Summer growing season, the application of 100/0 in lettuce plants increased growth. In the summer season the NO3 - content in petiole increased twofold. © 2019, Sociedad Mexicana de Fitogenetica.

publication date

  • 2019-01-01