A study was conducted in a greenhouse to evaluate the impact of different concentrations of zinc (Zn) and potassium (K) on the growth, yield, nutritional value, and biochemical status of hydroponically grown spinach (Spinacia oleracea cv. Virofly).
The experiment utilized three concentrations of Zn (0.22, 5, and 10 mg L−1) and K (39, 78, and 117 mg L−1) in a randomized complete design with three replications. Results indicated that increasing Zn and K concentrations enhanced the chlorophyll index and overall plant performance, with Zn having a more pronounced effect than K. The highest plant yield was achieved with 117 mg L−1 of K combined with either 5 or 10 mg L−1 of Zn. While Zn and K levels increased, other nutrients like Na, Fe, Cu, Ca, Mn, and Mg decreased compared to the control levels, except for Zn and K themselves. Elevated Zn and K concentrations significantly reduced malondialdehyde (MDA) and hydrogen peroxide (H2O2) content, while protein content increased by 1.4 and 1.2 times, respectively, compared to control plants. The activity of superoxide dismutase (SOD) peaked with 10 mg L−1 of Zn, regardless of K concentration, while ascorbate peroxidase (APX) activity increased up to 2.1 times at 10 mg L−1 Zn compared to 0.22 mg L−1. Overall, higher Zn and K concentrations reduced the absorption of other nutrients except for Zn and K in spinach leaves.
The study suggests that supplementing hydroponic solutions with 5 mg L−1 Zn and 78 mg L−1 K can improve the quality and resilience of spinach, enhancing crop productivity and nutritional value.
Behtash, F., Ramezani, R., Seyed Hajizadeh, H., & Eghlima, G. (2025). Optimum concentrations of potassium and zinc for better performance, nutritional, and biochemical quality of hydroponically cultivated Spinacia oleracea Cv. Virofly. Scientific Reports, 15(1), 1-18. https://doi.org/10.1038/s41598-025-96911-w
Source: Nature Magazine