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Title
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Photosynthesis performance in sweet almond [**Prunus dulcis** (Mill) D. Webb] exposed to supplemental UV-B radiation
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Author
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Abstract
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| Due to anthropogenic influences, solar UV-B irradiance at the earths 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-Bc), 4.42 (UV-B1), 7.32 (UV-B2) and 9.36 (UV-B3) 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 (F0) and F0/Fm, and a decrease in variable fluorescence (Fv, Fv/Fm, Fv/F0 and F0/Fm) due to its adverse effects on photosystem II activity. No significant change was observed for maximal fluorescence of dark-adapted state (Fm). Enhanced UV-B radiation caused a significant inhibition of net photosynthetic rate (P N) at UV-B2 and UV-B3 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 Fv/F0, 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. |
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Language
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English
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Source (journal)
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Photosynthetica. - Praha
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Publication
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Praha
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2011
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ISSN
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0300-3604
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Volume/pages
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49
:1
(2011)
, p. 107-111
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ISI
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000290319600013
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Full text (Publisher's DOI)
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