| Title | Growth and photosynthetic performance of Chlamydopodium fusiforme cells cultivated in BG11 and Bristol media |
| Abstract | Nitrogen is an essential nutrient for all life forms and its availability is periodically limited in marine and freshwater ecosystems. To optimize the growth of the freshwater microalga Chlamydopodium fusiforme and to investigate the cell acclimation process to different amounts of nitrogen, we grew cells in Bristol and BG11, under fixed conditions of 10 h:14 h light/dark cycle. Cultures grown in BG11 exhibited higher biomass accumulation, reaching a cell dry weight of 1.94 ± 0.1 g L-1, while in Bristol it reached 1.58 ± 0.1 g L-1. In cells grown in BG11, chlorophyll content increased continuously up to 79.6 mg L-1 (9th day), while in Bristol it was much lower (29.5 mg L-1). This fact caused a strong difference in their spectrally averaged optical cross-section normalized to chlorophyll a (a*), and consequently in their photosynthetic performance (oxygen evolution and electron transport rates). Carotenoid content followed a similar pattern. It was interesting to note that despite this great difference in chlorophyll concentration, both photosynthesis rate and cell dry weight were not affected proportionally. The chlorophyll a fluorescence measurements indicated a stable effective quantum yield of photosystem II in both culture conditions. During the dark phase of the cycle we observed in both cultures a remarkable reduction of both electron transfer and photosynthesis rates, while maximum quantum yield of PSII remained stable (0.74 ± 0.01). This indicated that the reduction in both photosynthesis rate and maximum electron transport rate (ETRmax) observed during the dark phase were not due to damage of PSII reaction centers but rather to reduced flow of electron subsequent to PSII. Recovery of the fully photosynthetic capacity required about 1 h of illumination. |
| Source | Journal of applied phycology (Dordr., Online) 32, pp. 145–152 |
| Keywords | Chlamydopodium fusiformeChlorophyceaeMicroalgaeVariable fluorescencePhotosynthesisBiomass composition |
| Journal | Journal of applied phycology (Dordr., Online) |
| Editor | Kluwer, Dordrecht, Paesi Bassi |
| Year | 2019 |
| Type | Articolo in rivista |
| DOI | 10.1007/s10811-019-01900-y |
| Authors | Touloupakis E., Tartari G., Chini Zittelli G., Torzillo G. |
| Text | 406299 2019 10.1007/s10811 019 01900 y Chlamydopodium fusiforme Chlorophyceae Microalgae Variable fluorescence Photosynthesis Biomass composition Growth and photosynthetic performance of Chlamydopodium fusiforme cells cultivated in BG11 and Bristol media Touloupakis E., Tartari G., Chini Zittelli G., Torzillo G. Touloupakis E. CNR Istituto di Ricerca sugli Ecosistemi Terrestri, Florence, Italy; Tartari G. CNR Istituto di Ricerca sulle Acque, Verbania, Italy; Chini Zittelli G., Torzillo G. CNR IBE, CNR Istituto per la Bioeconomia, Florence, Italy. Nitrogen is an essential nutrient for all life forms and its availability is periodically limited in marine and freshwater ecosystems. To optimize the growth of the freshwater microalga Chlamydopodium fusiforme and to investigate the cell acclimation process to different amounts of nitrogen, we grew cells in Bristol and BG11, under fixed conditions of 10 h 14 h light/dark cycle. Cultures grown in BG11 exhibited higher biomass accumulation, reaching a cell dry weight of 1.94 ± 0.1 g L 1, while in Bristol it reached 1.58 ± 0.1 g L 1. In cells grown in BG11, chlorophyll content increased continuously up to 79.6 mg L 1 9th day , while in Bristol it was much lower 29.5 mg L 1 . This fact caused a strong difference in their spectrally averaged optical cross section normalized to chlorophyll a a , and consequently in their photosynthetic performance oxygen evolution and electron transport rates . Carotenoid content followed a similar pattern. It was interesting to note that despite this great difference in chlorophyll concentration, both photosynthesis rate and cell dry weight were not affected proportionally. The chlorophyll a fluorescence measurements indicated a stable effective quantum yield of photosystem II in both culture conditions. During the dark phase of the cycle we observed in both cultures a remarkable reduction of both electron transfer and photosynthesis rates, while maximum quantum yield of PSII remained stable 0.74 ± 0.01 . This indicated that the reduction in both photosynthesis rate and maximum electron transport rate ETRmax observed during the dark phase were not due to damage of PSII reaction centers but rather to reduced flow of electron subsequent to PSII. Recovery of the fully photosynthetic capacity required about 1 h of illumination. 32 Published version 07/09/2019 Growth and photosynthetic performance of Chlamydopodium fusiforme cells cultivated in BG11 and Bristol media 2019_JAP_Growth_and_photosynthetic_performance_of_Chlamydopodium_fusiforme_cells_cultivated_in_BG11_and_Bristol_media_.pdf Articolo in rivista Kluwer 1573 5176 Journal of applied phycology Dordr., Online Journal of applied phycology Dordr., Online J. appl. phycol. Dordr., Online Journal of applied phycology. Dordr., Online graziella.chinizittelli CHINI ZITTELLI GRAZIELLA eleftherios.touloupakis TOULOUPAKIS ELEFTHERIOS gabriele.tartari TARTARI GABRIELE giuseppe.torzillo TORZILLO GIUSEPPE |
