Phytohormonal Roles in Plant Responses to Heavy Metal Stress: Implications for Using Macrophytes in Phytoremediation of Aquatic Ecosystems

Abstract

Heavy metals can represent a threat to the health of aquatic ecosystems. Unlike organic chemicals, heavy metals cannot be eliminated by natural processes such as their degradation into less toxic compounds, and this creates unique challenges for their remediation from soil, water, and air. Phytoremediation, defined as the use of plants for the removal of environmental contaminants, has many benefits compared to other pollution-reducing methods. Phytoremediation is simple, efficient, cost-effective, and environmentally friendly because it can be carried out at the polluted site, which simplifies logistics and minimizes exposure to humans and wildlife. Macrophytes represent a unique tool to remediate diverse environmental media since they can accumulate heavy metals from contaminated sediment via roots, from water via submerged leaves, and from air via emergent shoots. In this review, a synopsis is presented about how plants, especially macrophytes, respond to heavy metal stress and we propose potential roles that phytohormones can play in the alleviation of metal toxicity in the aquatic environment. We focus on the uptake, translocation, and accumulation mechanisms of heavy metals in organs of macrophytes and give examples of how phytohormones interact with plant defense systems under heavy metal exposure. We advocate for a more in-depth understanding of these processes to inform more effective metal remediation techniques from metal-polluted waterbodies.

Joint Biofortification of Plants with Selenium and Iodine: New Field of Discoveries

“…Furthermore, in conditions of joint Se–I hydroponics application, the activation of Se organic forms biosynthesis (SeMet, SeCys) reportedly takes place [ 38 , 41 ]. Though phytohormones are known to participate in plant Se accumulation [ 55 , 56 ], induce enrichment of chlorella with omega-3 fatty acids [ 57 ], take part to plant protection against heavy metals uptake [ 40 , 58 ], the investigations of Smolen et al [ 38 , 39 , 40 , 41 ] did not reveal any significant interaction between salicylic acid and Se.…”

Molecular Interaction and Evolution of Jasmonate Signaling With Transport and Detoxification of Heavy Metals and Metalloids in Plants

“…Heavy metals and metalloids are usually elements with a density higher than 5 g cm −3 (Tchounwou et al, 2012). Heavy elements displaying potential arrest on organisms growth, development, and productivity are classified as toxic heavy metals and metalloids (Järup, 2003;Clemens and Ma, 2016;Nguyen et al, 2021;Paithankar et al, 2021). The major threats to human health and the environment from heavy metals and metalloids are attributing to exposure to arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg; Järup, 2003).…”

Gibberellins Target Shoot-Root Growth, Morpho-Physiological and Molecular Pathways to Induce Cadmium Tolerance in Vigna radiata L.

“…Reduction in plant growth and pod size occurs under HM stress in mung bean [15][16][17]. Several biotechnological strategies have been adopted towards improving the HM stress management in crop plants [18], such as HM tolerance assisted by microbes [19], transgenics [20,21], and use of phytohormones [22,23]. A strong criticism for transgenic approaches of improving yield and abiotic or biotic stress tolerances of crop plants have impeded the acceptance of transgenic crops by the population world over [24,25].…”