Ionomic Profile and Nutrient Use Efficiency in Sunflower Plants Treated with Plant-Derived Biostimulant Rich in Trigonelline

In recent decades, the use of biostimulants has increased with the aim of creating an alternative to the use of chemical fertilizers and achieving sustainable agriculture. In this study, sunflower plants (Helianthus annuus L. cv. neoma) were grown under controlled conditions, and four trigonelline-rich extracts were applied as biostimulants through root and foliar applications. The plant growth parameters, nutrient concentrations, root metabolic activity, and nutrient use efficiency were evaluated. The results showed that the foliar application of extract 4 significantly improved the aboveground biomass and leaf area compared with the control treatments, with values of 44.30 g FW and 680.22 cm2, respectively. Moreover, this extract enhanced nutrient accumulation. Meanwhile, foliar application of extract 3 improved macronutrient and micronutrient concentrations, as in the case of phosphorus, which increased by 74.2%, and iron, which increased by 107.3%. Root applications of extracts 3 and 4 increased apparent nutrient recovery, whereas foliar applications of extracts 3 and 4 improved internal nutrient use and productivity indices. Overall, the treatments showed no phytotoxicity and promoted growth, nutrient absorption, and nutrient use efficiency, with the best results observed in foliar treatments with high trigonelline content. These findings indicate that biostimulants with trigonelline-rich extracts could improve crop yield, reduce the use of fertilizer, and contribute to more sustainable agricultural systems.