In this study, we evaluated the impact of brown seaweed extract (Ecklonia maxima) on the morphology and physiology of three different plant species. We conducted experiments using two types of fertilizers: an artificial fertilizer (0.1 g/L) and a biological extract of brown seaweed (Ecklonia maxima) at two concentrations (C1 at 1 mL/L and C2 at 2.5 mL/L). For melon, the application of C1 resulted in significant improvements in photosynthesis parameters, total chlorophyll content, and overall plant growth. When C2 was applied, it further enhanced these parameters, leading to a notable increase in shoot phytomass. In the case of cucumber, C1 led to increased resource allocation towards stems and leaves. Conversely, C2 increased the number of green leaves and contributed to higher shoot phytomass. For tomato plants, the application of C1 resulted in a slight increase in photosynthesis, but it did not significantly impact leaf growth. On the other hand, C2 induced a modest increase in photosynthesis, chlorophyll content, and root growth. In summary, our findings indicate that brown seaweed extract has a discernible influence on the physiology of the studied plants. However, the specific effects on resource allocation largely depend on the plant species and the concentration of the extract applied.

Context: Iron (Fe) is considered as a major cause of rural Tunisian soil contamination. Developing strategies for the cultivation of accumulator plants with permissible iron (Fe) concentrations is an urgent challenge. Aims: In this study, the effects of FeSO4 concentration (0, 50, 500 and 1000 mg L−1) on fenugreek morpho-biochemical parameters were investigated. Methods: The use of fenugreek as a phytoremediation strategy to control not only the uptake of Fe but also its safe consumption after treatments was evaluated. Key results: Results showed that elevated Fe concentrations did not affect the germination rate, but, rather, decreased the radicle length and amylase activity. The elemental analysis showed that Fe uptake was higher in shoots than in roots, but lower in harvested seeds. The translocation factor was higher than 1, suggesting a safe use of fenugreek as an accumulator. Moreover, the increase in Fe concentrations reduced the chlorophyll content and enhanced the production of lipid peroxidation, hydrogen peroxide and superoxide dismutase more frequently on fenugreek shoots than on their roots. In turn, the maximum concentrations of flavonoids and phenols were recorded under the Fe concentration of 50 mg L−1. High-performance liquid chromatography analysis showed that the gallic and syringic acids were the major phenols produced under Fe stress in shoots and that 50 mg L−1 of added Fe concentration induced their elevation. However, the quercetin was detected only in roots and was reduced under the increasing Fe concentrations. Conclusions: These results showed that fenugreek is an accumulator plant with admissible concentrations of Fe accumulation, which deploys multiple mechanisms to adapt to Fe stress.

Lead stands as a food contaminant through its accumulation in consumed plants. In this study, the effects of lead (II) chloride (PbCl₂) and its levels of uptake on morphological and phytochemical responses of fenugreek were assessed to evaluate its tolerance and safety for human consumption. Results revealed that PbCl₂ (50–2000 mg L⁻¹) did not affect the germination rate, but it decreased the radicle length and amylase activity. After three months of Pb treatments, the elemental analysis showed that Pb accumulation was greater in roots than shoots, and it was not present in harvested seeds. The bioaccumulation factor > 1 and the translocation factor << 1 observed for 1000 mg L⁻¹ PbCl₂ suggested appropriateness of fenugreek as a phytostabilizer. Additionally, increased lipid peroxidation, hydrogen peroxide, flavonoid levels and catalase activity were observed in Pb-treated fenugreek. Meanwhile, decreased chlorophyll content was detected under these conditions. In turn, the total phenol was correlated with Pb treatment only in roots. HPLC analysis proved that under Pb stress, gallic acid was the most produced compound in treated roots compared to shoots, followed by quercetin. Syringic and chlorogenic acids were more produced in shoots. In conclusion, fenugreek can be used for Pb phytoremediation and is safe for consumption after Pb treatments in the traditional medicine system.