Encontrados 11 documentos, a visualizar página 1 de 2
Seagrass photo-physiological responses in natural high-CO2 environment
Costa, Monya; Olivé, Irene; Barrote, Isabel; Procaccini, G.; Mazzuca, Silvia; Vizzini, Salvatrice; Santos, RuiThe atmospheric concentration of CO2 has been steeply increasing over the last 200 years, with an associated increase of total dissolved inorganic carbon (Ci) and a decrease of the oceans’ pH. Seagrasses are among the most productive marine ecosystems, but yet little is known on the effects of high-CO2/low pH on their photosynthetic physiology and the ecological consequences. Marine CO2 seepage areas have been ...
The effects of epiphytes on light harvesting and antioxidant responses in the s...
Costa, Monya; Silva, João; Olivé, Irene; Barrote, Isabel; Alexandre, A.; Albano, Sílvia; Santos, RuiPosidonia oceanica (L.) Delile is a subtidal seagrass whose leaves are commonly colonized by epiphytes. Epiphytes pose physical barriers to light penetration within the leaves, with possible significant impacts on photosynthesis. Furthermore, epiphytes can indirectly be responsible for leaf chlorosis, necrosis and senescence which are known to be related with the increase of oxygen reactive species (ROS) levels...
Responses of zostera marina and cymodocea nodosa to light-limitation stress
Silva, João; Barrote, Isabel; Costa, Monya; Albano, Sílvia; Santos, RuiThe effects of light-limitation stress were investigated in natural stands of the seagrasses Zostera marina and Cymodocea nodosa in Ria Formosa coastal lagoon, southern Portugal. Three levels of light attenuation were imposed for 3 weeks in two adjacent meadows (2–3 m depth), each dominated by one species. The response of photosynthesis to light was determined with oxygen electrodes. Chlorophylls and carotenoid...
Physiological responses of Zostera marina and Cymodocea nodosa to light-limitat...
Silva, João; Barrote, Isabel; Costa, Monya; Albano, Sílvia; Santos, RuiThe effects of light-limitation stress were investigated in natural stands of the seagrasses Zostera marina and Cymodocea nodosa in Ria Formosa coastal lagoon, southern Portugal. Three levels of light attenuation were imposed for 3 weeks in two adjacent meadows (2–3 m depth), each dominated by one species. The response of photosynthesis to light was determined with oxygen electrodes. Chlorophylls and carotenoid...
Influence of transient shade periods on the effects of drought on photosynthesi...
Correia, Maria João; Osório, Maria Leonor; Osório, Júlio; Barrote, Isabel; Martins, Mónica; David, Maria ManuelaThe effects of a slow-imposing two-weeks soil drying period, and subsequent re-watering, on leaf water potential (Ψ), gas exchange rates, chlorophyll fluorescence and on the concentrations of malondialdehyde (MDA) and non-structural carbohydrates (starch, hexose and sucrose) were determined in mature leaves of sunflower plants growing under controlled environmental conditions. To assess how transient shade peri...
Influence of nutrient availability on drought-induced changes in the activity o...
David, Maria Manuela; Barrote, Isabel; Correia, Maria JoãoWe aimed to evaluate if plants with different nutrient availability evidenced a different capacity to overcome drought-induced oxidative stress. Membrane peroxidative damages as MDA concentration and the activity of several antioxidant enzymes were determined in leaves of well watered (WW) and water stressed (WS) H. annuus plants grown either with adequate (Adeq Nutr) or limited (Limit Nutr) nutrient regimes. C...
Efeitos a posteriori dos défices hídricos sobre a actividade fotossintética: me...
Barrote, IsabelTese de dout., Biologia (Fisiologia Vegetal), Faculdade de Engenharia dos Recursos Naturais, Univ. do Algarve, 2005 ; A resposta dos mecanismos fotossintéticos à duração e intensidade do défice hídrico e posterior rehidratação foi investigada em plantas envasadas de Helianthus annuus L. e Lupinus albus L. A rega foi manipulada de modo a induzir diferentes intensidades de défice hídrico e posterior rehidratação...
Effects of water deficit on the activity of nitrate reductase and content of su...
Correia, Maria João; Fonseca, Filomena; Azedo-Silva, João; Dias, Celeste; David, Maria Manuela; Barrote, Isabel; Osório, Maria Leonor; Osório, JúlioThe effects of a two weeks soil drying period on the activity of nitrate reductase (NR; EC 1.6.6.6) were studied on Helianthus annuus L. and non-nodulated Lupinus albus L. plants, growing under two nutrient supply regimes. NR activity was assessed in leaf and root extracts, by measuring the activity of the unphosphorylated active form (NRact), the maximal extractable activity (NRmax) and the activation state. T...
Photosynthetic responses of Lupinus albus to soil water fluctuations
Barrote, Isabel; Osório, Maria Leonor; Osório, Júlio; David, Maria Manuela; Correia, Maria JoãoLupinus albus plants were grown in 3 dm3 pots in a semi-controled greenhouse. Two water regimes were imposed: water deficit (S, 47% of soil capacity), and control (T, 86% of soil capacity). Plants water status was monitored through foliar relative water content (TRA) and pre-dawn (ypd) and midday water potential (ymd). Gas exchanges, chlorophyll a fluorescence and photosynthetic capacity (Amax) were measured. P...
Alterações sazonais da fotossíntese e do ciclo das xantófilas em alfarrobeira (...
Barrote, Isabel; Correia, Maria João; David, Maria ManuelaThis study aimed to follow the seasonal changes in the photosynthetic performance of two Ceratonia siliqua cultivars – Mulata and Mulata do Espargal – growing in a non-irrigated orchard in Algarve (South Portugal). Measurements and sampling (leaf water potential, leaf gas exchange, pigments and dark-adapted chlorophyll fluorescence) were taken in days with similar photon flux density, during the dry season in J...
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