Spinach Responds to Minimal Nutrient Supplementation in Aquaponics by Up-Regulating Light Use Efficiency, Photochemistry, and Carboxylation

Aquaponics is a promising cultivation technique for combined production of crops and fish, on the condition tackling certain nutrients deficiencies. The aim present study was to examine limitations imposed by system spinach (Spinacia oleracea) growth functional performance identify minimum nutrient supplementation their optimization. Spinach co-cultivated with red tilapia under three treatments; iron (Fe) potassium (Fe+K) enrichment compared no-external input control. During 45-day experiment, photosynthetic performance, machinery efficiency, total chlorophylls content, leaf reflectance were monitored, along nutritional state, antioxidant activity, responses fish crops. Control plants showed symptoms Fe deficiency, extensive chlorosis, stunted growth, impairment already from day 10. latter consisted coordinated down-regulation photochemistry, carboxylation, light-use efficiency. Fe-treated exhibited similar Fe+K-treated but outperformed them in chlorophyll rates, photochemical mainly due higher quantum yield electron transport. Fish remained unaffected. Fe-deficiency identified as major bottleneck closed-loop aquaponics, our results demonstrate that only may sufficiently improve function yield.