An Overview of Studies on the Impact of Nickel on Selected Fabaceous Plants and Their Role in Phytoremediation

Nickel (Ni) accumulation in Fabaceous plants significantly impacts plant physiology, growth, and biochemical processes. At elevated concentrations, nickel induces oxidative stress, disrupts photosynthetic mechanisms, and alters membrane permeability. Plants exhibit reduced biomass, chlorophyll content, and photosynthetic efficiency. Furthermore, Ni's interference in the photosynthetic machinery (i.e., inhibition of chlorophyll biosynthesis and disruption of electron transport) can significantly decrease photosynthesis, cause leaf chlorosis and reduce overall plant biomass. In addition, all growth parameters such as root elongation and shoot development will be negatively impacted by Ni stress, especially with respect to competition for uptake with other essential nutrients. Physiological responses include decreased root and shoot growth, impaired nutrient uptake and increased production of reactive oxygen species (ROS). However, some Fabaceae species exhibit metal-tolerance mechanisms such as root exclusion, cellular compartmentalization and metal chelation. The phytoremediation potential varies among species, with some plants capable of accumulating substantial amounts of nickel, making them potential candidates for environmental remediation of nickel-contaminated sites.