1. Physiological responses to lead and PEG-simulated drought stress in metallicolous and non-metallicolous Matthiola (Brassicaceae) species from Iran.
- Author
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Salehi-Eskandari, Behrooz, Gahrouei, Mina Shahbazi, Boyd, Robert S., Rajakaruna, Nishanta, and Ghasemi, Rasoul
- Subjects
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BETAINE , *DROUGHTS , *PLANT adaptation , *BRASSICACEAE , *PLANT species , *DROUGHT management , *POLYETHYLENE glycol - Abstract
• Lead increased levels of osmoprotectants and phenol compounds in the metallicolous Matthiola flavida. • Reduced root-to-shoot translocation and enhanced Pb accumulation in the root, under drought stress, is responsible for reduced toxic effects of Pb in the shoot of the metallicolous species. • Lead stimulates drought resistance in the metallicolous species by the accumulation of reducing sugars, phenolic compounds and antioxidant enzymes. Plants growing on quarry tailings at the Irankouh Pb/Zn mine encounter both drought stress and high levels of Pb. To better understand the role of drought and Pb in plant adaptation to Pb/Zn quarry tailings, we compared effects of drought stress (simulated by polyethylene glycol - PEG) and Pb, individually and in concert, to determine how these stressors affected two plant species: the metallicolous species Matthiola flavida (M) and the non-metallicolous congener, M. incana (NM). Plants were exposed to Pb (Pb(NO 3) 2) and three levels of PEG-6000 (0, -0.25, and -0.75 MPa) in a complete factorial design. Pb had non-significant effects on growth and oxidative stress but enhanced levels of osmoprotectants and phenol compounds in the M species M. flavida , whereas in M. incana the effect of Pb was non-significant on the same variables (except for anthocyanins and the osmoprotectants, proline and glycine betaine). Compared to M. incana , the M species M. flavida was tolerant of Pb, showing strongly reduced root-to-shoot translocation and enhanced Pb accumulation in the root (especially when under drought stress), which reduced toxic effects of Pb in the shoot. Tolerance of Pb by the M species M. flavida was aided by the accumulation of reducing sugars and phenolic compounds, as well as by greater catalase activity. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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