کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4420314 1618966 2013 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Excess Ca2+ does not alleviate but increases the toxicity of Hg2+ to photosystem II in Synechocystis sp. (Cyanophyta)
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست شیمی زیست محیطی
پیش نمایش صفحه اول مقاله
Excess Ca2+ does not alleviate but increases the toxicity of Hg2+ to photosystem II in Synechocystis sp. (Cyanophyta)
چکیده انگلیسی


• Effects of excess Ca on Hg toxicity to cyanobacterium was investigated.
• Hg slows down electron transport on both donor side and acceptor side of PSII.
• Excess Ca increases Hg toxicity to PSII of Synechocystis sp.
• Hg may pose greater risk to ecosystem due to high level of Ca in karstic waters.

This study demonstrated that excess Ca2+ increased the toxicity of Hg2+ to PSII of cyanobacterium Synechocystis sp. using fast rise chlorophyll fluorescence test. Excess Ca2+ increased the inhibitory effect of Hg2+ on O2 evolution. Exposure to Hg2+ caused increase in functional antenna size (ABS/RC), trapping rate of reaction center (TR0/RC), dissipated energy flux per reaction center (DI0/RC) and maximum quantum yield of non-photochemical deexcitation (φDoφDo), indicating that some reaction centers were transformed to dissipation sinks under Hg2+ stress. Hg2+ stress slowed down electron transport on both donor side and acceptor side and caused accumulation of P680+. Excess Ca2+ intensified all the Hg2+ toxic effects on PSII function and led to dysfunction of PSII. The number of reaction centers that were transformed into dissipation sinks increased with increasing Ca2+ concentration.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ecotoxicology and Environmental Safety - Volume 97, 1 November 2013, Pages 160–165
نویسندگان
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