Abstract
Soil contamination with indium (In) oxide nanoparticles (In2O3-NPs) threatens plant growth and development. However, their toxicity in plants under ambient (aCO2) and elevated (eCO2) conditions is scarcely studied. To this end, this study was conducted to investigate In2O3-NPs toxicity in the young and old leaves of C3 (barley) and C4 (maize) plants and to understand the mechanisms underlying the stress mitigating impact of eCO2. Treatment of C3 and C4 plants with In2O3-NPs significantly reduced growth and photosynthesis, induced oxidative damage (H2O2, lipid peroxidation), and impaired P and Fe homeostasis, particularly in the young leaves of C4 plants. On the other hand, this phytotoxic hazard was mitigated by eCO2 which improved both C3 and C4 growth, decreased In accumulation and increased phosphorus (P) and iron (Fe) uptake, particularly in the young leaves of C4 plants. Moreover, the improved photosynthesis by eCO2 accordingly enhanced carbon availability under the challenge of In2O3-NPs that were directed to the elevated production of metabolites involved in antioxidant and detoxification systems. Our physiological and biochemical analyses implicated the role of the antioxidant defenses, including superoxide dismutase (SOD) in stress mitigation under eCO2. This was validated by studying the effect of In2O3-stress on a transgenic maize line (TG) constitutively overexpressing the AtFeSOD gene and its wild type (WT). Although it did not alter In accumulation, the TG plants showed improved growth and photosynthesis and reduced oxidative damage. Overall, this work demonstrated that C3 was more sensitive to In2O3-NPs stress; however, C4 plants were more responsive to eCO2. Moreover, it demonstrated the role of SOD in determining the hazardous effect of In2O3-NPs.
Highlights
Soil contamination with heavy metals and their nanoparticles is one of the major constraints altering soil quality [1] and limiting agricultural productivity worldwide [2].Recently, Indium (In) has become highly accumulated in the soil due to the intensive industry of electronics mainly liquid crystal display and light-emitting diodes as well as solar plates [3]
C3 plants with eCO2 under In2 O3 -NP-contamination conditions led to significant decreases in FW, dry weight (DW), photosynthetic, and RuBisco activities in their young leaves (~40%, 65%, 30%, and 60% reduction, respectively)
To add more clarity to the mitigative impact of eCO2 on barley and maize that are grown in soil polluted with In2 O3 -NPs, we focused on the behavior of detoxification metabolism as well as antioxidant defense systems
Summary
Indium (In) has become highly accumulated in the soil due to the intensive industry of electronics mainly liquid crystal display and light-emitting diodes as well as solar plates [3]. In and its oxide discharge into the environment pose a potential risk to crop. Antioxidants 2022, 11, 308 growth and development [4]. Many studies have reported that In accumulation in different plant species grown in contaminated soils caused growth inhibition by binding to the cell walls, increasing the cell wall rigidity, reducing cell growth, and causing cell rupturing [5,6,7]. Indium reduced the uptake and translocation of essential elements such as phosphorus and iron that inhibit plant growth and cause plants to show symptoms of phosphorus deficiency [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
