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| Gevaert, F; Creach, A; Davoult, D; Migne, A; Levavasseur, G; Arzel, Pierre; Holl, Ac; Lemoine, Y. |
| Photosynthetic activity in thalli of Laminaria saccharina (Lamouroux) was followed in situ in the upper subtidal zone of a Northern Brittany rocky shore (Roscoff, France), using a submersible pulse amplitude modulated (PAM) fluorometer. Two fluorescence parameters, the effective quantum yield of photosystem II (Phi(PSII)) and the relative electron transport rate (rETR), were estimated at various stages of a tidal cycle from 10:00 to 18:30 h, and different light conditions due to variations of water depth and position of the sun. The Phi(PSII) decreased strongly during the ebb tide, essentially due to a drop in the maximal fluorescence level for light-adapted samples (F-m'). This was the result of increasing non-photochemical quenching (NPQ). Algae totally... |
| Tipo: Text |
Palavras-chave: Laminaria saccharina; Photoprotection; Xanthophyll cycle; Chlorophyll fluorescence; Diurnal tidal cycles; Diving PAM. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00000/10191/7592.pdf |
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| Partelli,Fábio Luiz; Vieira,Henrique Duarte; Viana,Alexandre Pio; Batista-Santos,Paula; Rodrigues,Ana Paula; Leitão,António Eduardo; Ramalho,José Cochicho. |
| The objective of this work was to evaluate photoprotective mechanisms related to low positive temperatures in Coffea canephora (Conilon clones 02 and 153) and C. arabica ('Catucaí' IPR 102) genotypes, involved in cold temperature tolerance. To accomplish this, one-year-old plants were successively submitted to: temperature decrease of 0.5ºC day-1, from 25/20ºC to 13/8ºC; a three-day chilling cycle at 13/4ºC; and a recovery period of 14 days (25/20ºC). During the experiment, leaf gas exchange, chlorophyll a fluorescence and leaf photosynthetic pigment content were evaluated. Total activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and ribulose-5-phosphate kinase (Ru5PK) were quantified to measure the activity of photosynthesis key... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea; Carotenoids; Photoprotection; Photosynthesis; Rubisco. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2009001100006 |
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