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001-es BibID:	BIBFORM118127
035-os BibID:	(WoS)001152827800001 (Scopus)85183116796
Első szerző:	Irfan, Muhammad (PhD Environmental Sciences)
Cím:	Comparative Phytotoxicity of Metallic Elements on Duckweed Lemna gibba L. Using Growth- and Chlorophyll Fluorescence Induction-Based Endpoints / Muhammad Irfan, Ilona Mészáros, Sándor Szabó, Viktor Oláh
Dátum:	2024
ISSN:	2223-7747
Megjegyzések:	In this study, we exposed a commonly used duckweed species-Lemna gibba L.-to twelve environmentally relevant metals and metalloids under laboratory conditions. The phytotoxic effects were evaluated in a multi-well-plate-based experimental setup by means of the chlorophyll fluorescence imaging method. This technique allowed the simultaneous measuring of the growth and photosynthetic parameters in the same samples. The inhibition of relative growth rates (based on frond number and area) and photochemical efficiency (F-v/F-o and Y(II)) were both calculated from the obtained chlorophyll fluorescence images. In the applied test system, growth-inhibition-based phytotoxicity endpoints proved to be more sensitive than chlorophyll-fluorescence-based ones. Frond area growth inhibition was the most responsive parameter with a median EC50 of 1.75 mg L-1, while F-v/F-o, the more responsive chlorophyll-fluorescence-based endpoint, resulted in a 5.34 mg L-1 median EC50 for the tested metals. Ag (EC50 0.005-1.27 mg L-1), Hg (EC50 0.24-4.87 mg L-1) and Cu (EC50 0.37-1.86 mg L-1) were the most toxic elements among the tested ones, while As(V) (EC50 47.15-132.18 mg L-1), Cr(III) (EC50 6.22-19.92 mg L-1), Se(VI) (EC50 1.73-10.39 mg L-1) and Zn (EC50 3.88-350.56 mg L-1) were the least toxic ones. The results highlighted that multi-well-plate-based duckweed phytotoxicity assays may reduce space, time and sample volume requirements compared to the standard duckweed growth inhibition tests. These benefits, however, come with lowered test sensitivity. Our multi-well-plate-based test setup resulted in considerably higher median EC50 (3.21 mg L-1) for frond-number-based growth inhibition than the 0.683 mg L-1 median EC50 derived from corresponding data from the literature with standardized Lemna-tests. Under strong acute phytotoxicity, frond parts with impaired photochemical functionality may become undetectable by chlorophyll fluorometers. Consequently, the plant parts that are still detectable display a virtually higher average photosynthetic performance, leading to an underestimation of phytotoxicity. Nevertheless, multi-well-plate-based duckweed phytotoxicity assays, combined with chlorophyll fluorescence imaging, offer definite advantages in the rapid screening of large sample series or multiple species/clones. As chlorophyll fluorescence images provide information both on the photochemical performance of the test plants and their morphology, a joint analysis of the two endpoint groups is recommended in multi-well-plate-based duckweed phytotoxicity assays to maximize the information gained from the tests.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk békalencse fitotoxicitás ökotoxikológia növekedésgátlás klorofill fluoreszcencia indukció nehézfém
Megjelenés:	Plants-Basel. - 13 : 2 (2024), p. 1-16. -
További szerzők:	Mészáros Ilona (1952-) (biológus) Szabó Sándor (biológus) Oláh Viktor (1980-) (biológus)
Pályázati támogatás:	FK 134296 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM126219
035-os BibID:	(WoS)001382457400001 (Scopus)85212092273
Első szerző:	Szabó Sándor (biológus)
Cím:	Submerged macrophytes can maintain stable dominance over free-floating competitors through high pH / Sándor Szabó, Noémi Fedor, Gergő Koleszár, Mihály Braun, János Korponai, Aleksandra Kočić, Sabine Hilt, Viktor Oláh
Dátum:	2025
ISSN:	0046-5070 1365-2427
Megjegyzések:	1. Submerged and free-floating macrophytes are the two main vegetation types that can alternatively dominate in small shallow ponds and ditches. Submerged macrophytes provide more aquatic ecosystem services and cause fewer problems with anoxia and greenhouse gas emissions than free-floating plants, but are inferior competitors for light. High pH values have been proposed as a contributor to submerged plant dominance, but threshold values for pH-induced growth reduction of floating plants by submerged macrophytes are not known. 2. In this study, we conducted laboratory experiments to test whether submerged plants (Ceratophyllum demersum) can effectively limit the growth of free-floating competitors (Lemna gibba) by exceeding a critical threshold pH value. We used field data to test if and when such pH values can be achieved within dense submerged macrophyte stands. 3. The pH values that caused 50% reduction in fresh weight- and chlorophyll-based growth of L. gibba were 9.6 and 9.8, respectively, and the growth was negligible above pH 10.0. The photochemical efficiency of photosystem II and chlorophyll content of the floating plants declined rapidly above pH 9 and 9.5, respectively. Similarly, phosphorus concentration decreased and dry matter content increased sharply in L. gibba fronds above pH 9.5, respectively. We thus expect a critical pH threshold for L. gibba at around 9.5. 4. Our mesocosm and field data show that the critical pH threshold for L. gibba growth is regularly exceeded within dense stands of bicarbonate-using submerged macrophytes in lentic water-bodies. Such conditions can be prevalent in the upper water layer during most of the day (12 h) in summer. 5. The literature showed that many duckweed species (and other common free-floating plants) in temperate and tropical water bodies show growth inhibition above pH 8. Therefore, high pH created by submerged macrophytes that use HCO3? in photosynthesis can be a major mechanism by which dominance over free-floating competitors is maintained in densely vegetated lentic eutrophic water bodies. We propose that alternative stable states occur between free-floating and submerged macrophytes along a pH gradient. Active management of pH may, thus, help in maintaining the desired state
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Ceratophyllum competition inhibition Lemna stable state
Megjelenés:	Freshwater Biology. - 70 : 1 (2025), p. 1-11. -
További szerzők:	Fedor Noémi (biológus) Koleszár Gergő Braun Mihály (1966-) (vegyész, analitikus) Korponai János (1964-) (biológus) Kočić, Aleksandra Hilt, Sabine Oláh Viktor (1980-) (biológus)
Pályázati támogatás:	FK134296 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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