کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1742061 | 1017563 | 2013 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Probing the effects of high-light stress on pigment and lipid metabolism in nitrogen-starving microalgae by measuring chlorophyll fluorescence transients: Studies with a Δ5 desaturase mutant of Parietochloris incisa (Chlorophyta, Trebouxiophyceae) Probing the effects of high-light stress on pigment and lipid metabolism in nitrogen-starving microalgae by measuring chlorophyll fluorescence transients: Studies with a Δ5 desaturase mutant of Parietochloris incisa (Chlorophyta, Trebouxiophyceae)](/preview/png/1742061.png)
We investigated effects of irradiance on the relationships between chlorophyll fluorescence transients (OJIP), carotenoid-to-chlorophyll ratio, and fatty acids in a nitrogen-deprived Parietochloris incisa (Chlorophyta, Trebouxiophyceae) Δ5 desaturase mutant accumulating valuable LC-PUFA dihomo-γ-linolenic acid (DGLA). High light (270 μE·m− 2·s− 1 PAR) and nitrogen starvation brought about a decrease in maximum quantum yield of photosystem II (ΦP0ΦP0) and electron transport (ΦE0ΦE0) but enhanced the quantum yield of thermal dissipation (ΦD0ΦD0) and induced non-photochemical quenching (NPQ) in an irradiance-dependent manner. Under high irradiance a decline in the rate of total fatty acid accumulation and DGLA percentage in comparison with the cultures grown under 130 μE·m− 2·s− 1 PAR was recorded. Increasing irradiance from 130 to 270 μE·m− 2·s− 1 enhanced total fatty acid accumulation only within the first week of nitrogen starvation and negatively affected DGLA production. Regardless of irradiance, ΦP0ΦP0, ΦE0ΦE0, and ΦD0ΦD0 exhibited tight (r2 = 0.8–0.9) relationships with the stress-induced changes of total fatty acid and DGLA content and the carotenoid-to-chlorophyll ratio. The applicability and limitations of OJIP and its derived parameters for on-line monitoring of physiological condition and accumulation of value-added products in microalgal cultures grown in photobioreactors are discussed.
Journal: Algal Research - Volume 2, Issue 3, July 2013, Pages 175–182