Photochemical efficiency of PSII and photoprotective pigments in seedlings and adults of two Proteaceae with different shade tolerance from the Chilean temperate rain forest

Abstract

Eficiencia fotoquímica del PSII y pigmentos fotoprotectores en plántulas y adultos de dos Proteáceas con diferente tolerancia a la sombra del bosque lluvioso templado chileno ABSTRACTThe seasonal variation in energy quenching parameters of photosystem II and photoprotective pigments were studied in seedlings and adults of two Proteaceae: a shade-intolerant species (Embotrium coccineum J.R. et G. Forster) and a shade-tolerant species (Lomatia ferruginea (Cav.) R. Br.). We postulate that the shade intolerant species favors photochemical energy driven processes (mainly CO 2 assimilation) while the shade tolerant species exhibits higher non-photochemical energy dissipation under unfavorable conditions. Moreover, the shade tolerant species presents lower seasonal variations in these parameters that the shade intolerant species. Differences in energy dissipation should be more evident in seedlings than adults because of their contrasting light environments and temperatures are more evident at this stage. Their maximal photochemical efficiency (Fv/Fm) was in the range 0.70-0.83. The effective photochemical efficiency (ΦPSII), photochemical quenching (qP), and electron transport rate (ETR) were higher in seedlings of E. coccineum than in seedlings of L. ferruginea. Adults showed higher photochemical energy quenching parameters than seedlings. Nonphotochemical quenching (NPQ) was frequently similar between daily periods, seasons, species, and developmental stages, with the exception of the lowest non-photochemical quenching in seedlings of E. coccineum in summer. Seedlings and adults showed a larger xanthophyll cycle pool content at midday in summer than in winter, while the pool of antheraxanthin + zeaxanthin was always higher at midday. Lutein increased the most during summer. Thus, E. coccineum seedlings and adults maintained high photosynthesis, a higher fraction of open reaction centres, and higher ETR than the shade tolerant species. These differences are consistent with the ecological functions of both species: a pioneer character, higher growth rate, and wide altitudinal and latitudinal distribution of E. coccineum compared to L. ferruginea.Key words: chlorophyll fluorescence, lutein, photosynthesis, photoprotective pigments, xanthophylls cycle. RESUMENSe estudia la variación estacional en los parámetros de amortiguamiento (quenching) energético del fotosistema II y los pigmentos fotoprotectores en plántulas y adultos de dos Proteáceas con diferente tolerancia a la sombra: Embothrium coccineum J. R. et G. Foster (intolerante) y Lomatia ferruginea (Cav.) R. Br (tolerante). Se prueba la hipótesis que la especie intolerante a la sombra favorece los procesos fotoquímicos de energía conducentes a la asimilación de CO 2 mientras que la tolerante a la sombra exhibe principalmente una disipación no fotoquímica de la energía ante condiciones de luz desfavorables. Las diferencias en la disipación de energía deben ser más evidentes en plántulas que en adultos debido a que las condiciones de luz y temperatura de sus ambient...

Disturbance regimes, gap‐demanding trees and seed mass related to tree height in warm temperate rain forests worldwide

“…() and Alberdi et al . (), who compared the light‐demanding Embothrium coccineum , the intermediate Gevuina avellana and the shade‐tolerant Lomatia ferruginea . The thermal dissipation of excess energy was saturated at a notably lower irradiance in Lomatia ferruginea than in the other two species, leaving unresolved the leaf‐level mechanisms by which this species can be successful in completely open areas.…”

“…Thus the assertion of Alberdi et al . () that L. ferruginea does not invade volcanic deposits is untrue.…”

“…This is especially true of those with very small seeds which fail to compete on roadsides with deeper soils where there is a greater supply of nutrients. The only studies we have found of experimental work on photoinhibition in species of WTRF are those of Castro- Arévalo et al (2008) and Alberdi et al (2009), who compared the lightdemanding Embothrium coccineum, the intermediate Gevuina avellana and the shade-tolerant Lomatia ferruginea. The thermal dissipation of excess energy was saturated at a notably lower irradiance in Lomatia ferruginea than in the other two species, leaving unresolved the leaf-level mechanisms by which this species can be successful in completely open areas.…”

“…Segura Uauy (1999) recorded Lomatia ferruginea on young lava flows within the altitudinal zone of WTRF where such flows are uncommon. Thus the assertion ofAlberdi et al (2009) that L. ferruginea does not invade volcanic deposits is untrue.…”

Impact of Ploidy Change on Secondary Metabolites and Photochemical Efficiency in Solanum Bulbocastanum

“…Comparable or the same leaves as those used for IRGA determinations were selected for fluorescence analyses. The protocol of Alberdi et al [37] was followed. Definitions of fluorescence parameters Fv/Fm and ΦPSII were used as described by Maxwell and Johnson [38].…”