Influence of different manganese concentrations on eggplant (Solanum melongena L.) grown in a hydroponic system

The study aimed to evaluate the effect of three different manganese (Mn) concentrations on the plant growth, leaf chlorophyll, carotenoid content, photosynthetic activity, and root morphological development in eggplant (Solanum melongena L. ‘Adana cv. Dolmalık’ and ‘Köksal cv. F1’). Plants were grown continuously in aerated nutrient solution by using a deep-water culture (DWC) technique in a fully automated climate room. A randomized block design with three replications was used. Both excessive (400 µM) and insufficient (0.4 µM) Mn concentrations in the root zone reduced the shoot fresh and dry matter, branch number, leaf area, and leaf chlorophyll content in both examined genotypes in comparison with optimal Mn concentrations (200 µM). Köksal cv. F1 produced higher shoot and root biomasses, root:shoot ratio, total leaf number, leaf total chlorophyll and carotenoid content, total leaf area, and average root diameter at the low concentration of Mn. Conversely, Adana cv. Dolmalık produced significantly higher stem length, shoot and root biomasses, total root length and root volume at high Mn concentrations. Overall, both deficit and excess Mn nutrition could induce disorders in the growth and development of eggplant which may reduce crop yield.