8th International Conference on Duckweed Research and Applications

Intra-specific variation in growth and photosynthetic responses of duckweed Lemna gibba to manganese

02 ott 2026, 10:05

20m

Sala Monumentini ()

Poster Poster session

Description

Abstract
This study investigated the growth and physiological responses of four Lemna gibba clones (UD0101, UD0103, UD0106, and UD0114) following 7-day exposure to Mn (0.05–160 mg L⁻¹) under controlled conditions (Steinberg’s medium containing 0.05 mg Mn L⁻¹). Growth was assessed using frond area relative growth rate (RGRFA) and frond number relative growth rate (RGRFN). Photosynthetic performance was evaluated using Fv/Fm, Y(II), Y(NPQ), and Y(NO). All clones were affected at Mn concentrations ≥20 mg L⁻¹, whereas UD0103 showed growth inhibition from 5 mg L⁻¹. Under control conditions, RGRFA ranged from 0.287 day⁻¹ (UD0106) to 0.334 day⁻¹ (UD0101), while RGRFN ranged from 0.269 day⁻¹ (UD0106) to 0.294 day⁻¹ (UD0101); UD0103 and UD0114 showed intermediate growth rates. At 160 mg Mn L⁻¹, RGRFA relative to the control indicated Mn tolerance in the order UD0101 (50%) > UD0114 (40%) > UD0103 (27%) > UD0106 (25%). Despite growth inhibition, Fv/Fm remained at or slightly above control levels (99–108%) in UD0101 and UD0106, whereas UD0103 and UD0114 showed reduced Fv/Fm at ≥20 mg Mn L⁻¹, reaching minima of 94.9% and 95.2% of the control, respectively. Similarly, increasing Mn concentrations reduced Y(II) in all clones. At 40 mg L⁻¹, Y(NPQ) increased significantly, peaking at approximately 1.8-fold and 1.7-fold above the control in UD0106 and UD0114, respectively. In contrast, UD0101 maintained stable Y(II), Y(NPQ), and Y(NO), whereas UD0103 showed the greatest increase in Y(NO) and a reduced Y(II). These findings suggest that UD0103 could serve as a bioindicator of Mn pollution, whereas UD0101 shows potential for phytoremediation.

Keywords

Duckweeds, clone, Chlorophyll fluorescence, Manganese

References

Irfan M, Mészáros I, Szabó S, Oláh V. Comparative Phytotoxicity of Metallic Elements on Duckweed Lemna gibba L. Using Growth- and Chlorophyll Fluorescence Induction-Based Endpoints. Plants 2024;13. https://doi.org/10.3390/plants13020215.