This study highlights Adesmia pinifolia, a native high-Andean species, as a potential candidate for the phytoremediation of soils contaminated with Cd and Hg. In this work, a semi-hydronic assay with different doses of Cd (3, 4.5, and 6 mg L-1) and Hg (0.8, 1.2, and 1.6 mg L-1) was analysed to evaluate the establishment of plants, antioxidant defence systems, oxidative stress, and the ability to accumulate heavy metals. The results indicate high survival rates (>80%); however, Cd significantly reduced shoot and root biomass, while Hg increased root biomass with the 1.6 mg L-1 treatment. Cd and Hg tend to accumulate more in roots (2534.24 mu g/g and 596.4 mu g g(-1), respectively) compared to shoots (398.53 mu g g-1 and 140.8 mu g g-1, respectively). A significant decrease in the bioconcentration factor of Cd and Hg in roots was observed as metal levels increased, reaching the maximum value at 3 mg L-1 (805.59 +/- 54.38) and 0.8 mg L-1 (804.54 +/- 38.09). The translocation factor, <1 for both metals, suggests that translocation from roots to shoots is limited. An overproduction of reactive oxygen species (ROS) was observed, causing lipid peroxidation and oxidative damage to plant membranes. Tolerance strategies against subsequent toxicity indicate that enhanced glutathione reductase (GR) activity and glutathione (GSH) accumulation modulate Cd and Hg accumulation, toxicity, and tolerance.

To uncover the regulatory metabolism of poly-glutamic acid (PGA) in protecting wheat crops against salt stress (SS) at the physiological level, we utilised hydroponic experiments to explore the roles of PGA in regulating the photosynthetic performance, water physiology, antioxidant metabolism and ion homeostasis of wheat seedlings exposed to SS for 10 days. The findings demonstrated that SS inhibited the photosynthetic performance of wheat seedlings. In contrast, different doses of PGA all improved the photosynthetic performance, especially for 0.3% PGA. Compared with SS, 0.3% PGA plus SS decreased nonphotochemical quenching (qN) by 26.3% and respectively increased photosynthetic rate (Pn), soil and plant analyser development (SPAD) value, maximum photochemical efficiency of photosystem II (PSII) (Fv/Fm), photochemical quenching (qP) and actual photochemical efficiency of PSII (Y(II)) by 54.0, 27.8, 34.6, 42.4 and 25.8%. For water metabolism, SS destroyed the water balance of wheat seedlings. In contrast, different doses of PGA enhanced water balance, especially for 0.3% PGA. Compared with SS, 0.3% PGA plus SS decreased leaf water saturation deficit (LWSD) by 35.5% and respectively increased leaf relative water content (LRWC), transpiration rate (Tr), stomatal conductance (gs) and the contents of soluble sugars (SSS) and proline (Pro) by 15.9, 94.7, 37.5, 44.6 and 62.3%. For antioxidant metabolism, SS induced the peroxide damage to wheat seedlings. In contrast, different doses of PGA all mitigated the SS-induced peroxide damage, especially for 0.3% PGA. Compared with SS, 0.3% PGA plus SS respectively decreased superoxide anion (O2-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents and electrolyte leakage (EL) by 39.1, 29.6, 46.2 and 36.3%, and respectively increased superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductases (DHAR) and monodehydroascorbate reductase (MDHAR) activities, and antioxidants ascorbic acid (AsA) and glutathione (GSH) contents by 69.2, 49.2, 77.8, 80.6, 109.5, 121.7, 104.5, 63.8 and 39.6%. Besides, SS destroyed the ion homeostasis of wheat seedlings. In contrast, different doses of PGA all maintained ion homeostasis, especially for 0.3% PGA. Compared with SS, 0.3% PGA plus SS reduced Na+ content creasing K+/Na+, Ca2+/Na+ and Mg2+/Na+ ratios by 177.6, 209.4 and 244.8%. In the above ways, SS inhibited wheat height and biomass. In contrast, different doses of PGA all improved wheat height and biomass under SS, especially for 0.3% PGA. Compared with SS, 0.3% PGA plus SS, respectively, increased wheat height and biomass by 27.4% and 41.7%. In the above ways, PGA mitigated salt toxicity in wheat seedlings. The current findings implied that there