Influence of transient shade periods on the effects of drought on photosynthesis, carbohydrate accumulation and lipid peroxidation in sunflower leaves

Abstract

The authors aknowledge Environmental and Experimental Botany, an Elsevier Journal. AbstractThe 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

Intensity of bitterness of processed yerba mate leaves originated in two contrasted light environments

“…The young leaves in Camellia sinensis (tea plant) rich in the metals have been of high quality compared to the old leaves (Tsushida & Takeo, 1977). During a diurnal-scale period, under high irradiance, the concentration of non-structural carbohydrates in well-waters leaves of the sunflower was found to two-fold from the sunrise to midday of active photosynthesis (Correia et al, 2006). On the other hand, the content of the soluble sugars in the leaves increased during the night and in sunrise.…”

“…On the other hand, the content of the soluble sugars in the leaves increased during the night and in sunrise. Also, the content of the soluble starch and sugar were increased in the diurnal period when one or more agents as drought (Correia et al, 2006) or infection (Muthuchelian et al, 2005) acted. In this sense, daytime and plant stage have to be respected in future yerba mate taste evaluation experiments.…”

“…Light is often a limiting factor considering inter-and intra-specific competition between the plants and plant organs. The photosynthesis, stomatal conductance, Rubisco activity (Heraut-Bron et al, 1999), and leaf carbohydrates are quickly affected by the irradiance reduction (Correia et al, 2006). Shade inducedlimitation in the sugar accumulation is expected to alleviate the end-product inhibition of the photosynthesis (Paul & Foyer, 2001).…”

Fluorescencia como indicador de estrés en <i>Helianthus annuus</i> L. Una revisión

“…Estos cambios están acompañados por un aumento de la peroxidación lipídica (Correia et al, 2006). La rehidratación de estas plantas hace que se recupere la capacidad del PSII, esto demuestra que no hubo un daño permanente en el PSII y es corroborado por valores de F v / F m entre 0,8-0,83 (Correia et al, 2006).…”

“…Diferentes factores como temperaturas extremas, sequía, cambios en la intensidad lumíni-ca, salinidad, deficiencias nutricionales, metales pesados, herbicidas, entre otros, afectan directa o indirectamente el funcionamiento del PSII, generando un cambio en la emisión de la fluorescencia (Santos, 2004;Correia et al, 2006;González et al, 2008;Neto et al, 2011). Por tanto, los cambios en la emisión de la fluorescencia, pueden utilizarse para encontrar mecanismos de respuesta y cuantificación de respuestas al estrés (Maxwell y Johnson, 2000;González et al, 2008).…”