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.

Falcataria falcata, until recently known as Falcataria moluccana and commonly known as albizia, is a large, fast-growing tree native to the Malaysian peninsula, Indonesia, Papua New Guinea, and Solomon Islands. It has been introduced to, and become naturalized in, continental Africa, Asia, and many Caribbean and Pacific Islands. F. falcata is an early successional pioneer species that typically establishes via purposeful plantings. It readily spreads and outcompetes other tree species as a function of its symbiotic nitrogen-fixing capacity, copious long-lived seedbanks, and rapid growth rates. Due to their large stature at maturity (>30 m in height) and unstable architecture, F. falcata stands have the capacity to substantively alter the composition, structure, and function of lowland wet forests, and they pose a potent threat to both native forests and human communities across the Pacific. Despite negative aspects associated with its invasion, F. falcata has been harnessed for commercial profit and to increase soil fertility, particularly in its native range. F. falcata can be a component of productive agroforestry systems; the wood is used for firewood, as energy for industry, and timber in light construction. The nutrient-rich biomass of the tree is also used as mulch to increase crop production. However, given that mature stands were primarily responsible for millions of dollars of damage resulting from catastrophic tree fall during Tropical Storm Iselle on Hawai'i Island, and the potential interactions with climate change and development, managing this tree for its benefits as well as expanding research for its control is warranted.