Photosynthesis performance in sweet almond [Prunus dulcis (Mill) D. Webb] exposed to supplemental UV-B radiation

Due to anthropogenic influences, solar UV-B irradiance at the earth's surface is increasing. To determine the effects of enhanced UV-B radiation on photosynthetic characteristics of Prunus dulcis, two-year-old seedlings of the species were submitted to four levels of UV-B stress, namely 0 (UV-B(c)), 4.42 (UV-B(1)), 7.32 (UV-B(2)) and 9.36 (UV-B(3)) kJ m(-2) d(-1). Effects of UV-B stress on a range of chlorophyll (Chl) fluorescence parameters (FPs), Chl contents and photosynthetic gas-exchange parameters were investigated. UV-B stress promoted an increase in minimal fluorescence of dark-adapted state (F(0)) and F(0)/F(m), and a decrease in variable fluorescence (F(v), F(v)/F(m), F(v)/F(0) and F(0)/F(m)) due to its adverse effects on photosystem II (PSII) activity. No significant change was observed for maximal fluorescence of dark-adapted state (F(m)). Enhanced UV-B radiation caused a significant inhibition of net photosynthetic rate (P(N)) at UV-B(2) and UV-B(3) levels and this was accompanied by a reduction in stomatal conductance (g(s)) and transpiration rate (E). The contents of Chl a, b, and total Chl content (a+b) were also significantly reduced at increased UV-B stress. In general, adverse UV-B effects became significant at the highest tested radiation dose 9.36 kJ m(-2) d(-1). The most sensitive indicators for UV-B stress were F(v)/F(0), Chl a content and P(N). Significant P < 0.05 alteration in these parameters was found indicating the drastic effect of UV-B radiation on P. dulcis

Inter- and intraspecific variability in invertebrate acute toxicity response to Arsenic and Fluoride exposure

The adverse effects of arsenic and fluoride exposure on six groups of freshwater invertebrates were investigated. Acute toxicity tests (48-h) with arsenic trioxide (As2NO3) resulted in the following pattern of sensitivity: Daphnia magna 24-h-old = Brachionus patulus 72-h-old = Daphnia. cf. prolata, 21-d-old = D. magna 5-d-old > Heterocypris incongruens juvenile instars > Culex sp. Heterocypris juv. incongruens instars were the second group more tolerant to arsenic and the second group that bioconcentrates arsenic the least. In contrast, invertebrates exposed to sodium fluoride (NaF), showed a different pattern of sensitivity: H. incongruens instars > B. patulus = D. magna 24-h-old > D. cf. prolata 21-d-old = Culex sp. = D. magna 5-d-old. Our results suggest that all species tested might be considered good model tests organisms for As toxicity except H. incongruens. The rotifer B. patulus did not accumulate either arsenic or fluoride; and its sensitivity was intermediate for both toxicants. In contrast, D. cf. prolata accumulated more fluoride and was also (together with 5-d-old D. magna) the most tolerant to fluorine. In the case of arsenic, 5-d-old D. magna were the organisms with highest accumulation rates, but their sensitivity was similar to all other species (except for Culex sp. and H. incongruens). Interestingly, H. incongruens juv. instars have low sensitivity to As but are the most sensitive species to fluoride exposure. These results point out to the need of consider several invertebrate species as model organisms for environmental protection of particular ecosystems, or that some freshwater species have the potential to be used as fluorine bioaccumulators in remediation processes

Supplementary data for the article: Mitrović, A. L.; Simonović Radosavljević, J.; Prokopijević, M.; Spasojević, D.; Kovačević, J.; Prodanović, O.; Todorović, B.; Matović, B.; Stanković, M.; Maksimović, V.; Mutavdžić, D.; Skočić, M.; Pešić, M.; Prokić, L.; Radotić, K. Cell Wall Response to UV Radiation in Needles of Picea Omorika. Plant Physiology and Biochemistry 2021, 161, 176–190. https://doi.org/10.1016/j.plaphy.2021.02.007.

Supplementary material for: [https://doi.org/10.1016/j.plaphy.2021.02.007]Related to published version: [http://aspace.agrif.bg.ac.rs/handle/123456789/5816

Modern Trends in Applied Aquatic Ecology

xiv,379 hal,;ill,;25 c

Plant Cover - Ecological Implications and Methodical Approaches

Steinlein T. Plant Cover - Ecological Implications and Methodical Approaches. In: Ambasht RS, Ambasht NK, eds. Modern Trends in Applied Terrestrial Ecology. New York, NY: Kluwer Acad./Plenum Publ.; 2002: 367

Modern trends in applied aquatic ecology

edited by R.S. Ambasht and Navin K. Ambasht.xiv, 379 p. : ill., maps ; 26 cm