Photosynthetic analyses of two native Atlantic Forest species in regenerative understory of eucalyptus plantation

Abstract

Gas exchange, chlorophyll a fluorescence, and photosynthetic pigments of Xylopia sericea A. St.-Hil. and Siparuna guianensis Aubl. were evaluated during the rainy season and the dry season (2009)(2010) in three understories with different ecological conditions (irradiance, water availability, and temperature) located in the União Biological Reserve (known as REBIO União), at Rio de Janeiro State, a natural forest understory, eucalyptus understory under regeneration, and understory of eucalyptus plantation with 18-year-old trees that were removed 1 year before. The lowest values of F v /F m e F m /F o were observed in the exposed understory for both seasons, with lower values in the dry season, suggesting that reduced water availability potentializes the photoinhibitory process. For both species of the exposed understory it is suggested the occurrence of photoprotection, given that an increased proportion of carotenoid pigments in relation to the chlorophylls were verified. Both species still exhibited dynamic photoinhibition after 1 year of exposure to full sunlight (exposed understory) in both seasons, but more markedly so in the dry season, though they belong to early stages of ecological succession. Based on the results, it is suggested that these species are indicated for planting in degraded areas and that the cutting of eucalyptus trees as management practice should be performed in a gradual manner, during the rainy season, in order to minimize stress on these species.

Using leaf δ13C and photosynthetic parameters to understand acclimation to irradiance and leaf age effects during tropical forest regeneration

“…The data show that the main species regenerating in the understory can increase carbon gain and tolerate more irradiance after management. These data in addition to previous studies (Evaristo et al, 2011;Lage-Pinto et al, 2012;Lage-Pinto et al, 2015;Silva et al, 2010;Teixeira et al, 2015;Vieira et al, 2015) show the photoacclimation performance of these species to more irradiance, that could explain their abundance in the open and management areas. Thus, there is a possibility that the management may affect the trajectory of forest regeneration, including potential dominance of these species.…”

“…This suggests that photodamage is reversible in young leaves. Although these species show photoacclimation capacity (Silva et al, 2010;Lage-Pinto et al, 2012;Teixeira et al, 2015;Vieira et al, 2015), dynamic photoinhibition had been observed 1 year after management for S. guianensis and X. sericea in this area (Lage-Pinto et al, 2012). All species are able to photoacclimate,, but B. sericea is the fastest species to recuperate initial conditions after forest management (Teixeira et al, 2015).…”

“…Studies concerning photosynthetic responses to irradiance, carried out in degraded or managed secondary forest, gaps or along irradiance gradients, have generally shown functional and structural acclimatation responses (Lage-Pinto et al, 2012;Rabelo et al, 2013;Silva et al, 2010;Milena Carvalho Teixeira et al, 2015;Vieira et al, 2015). Leaf functional responses to environmental variation can be evaluated as a time-integrated response of leaf carbon isotope composition (δ 13 C) (Dawson et al, 2002;Duarte et al, 2005;Leavitt and Long, 1986;Zimmerman and Ehleringer, 1990), because the supply of CO 2 at the site of carboxylation determines discrimination against 13 CO 2 relative to 12 CO 2 during photosynthesis (Farquhar and Richards, 1984).…”

Gas exchange and antioxidant activity in seedlings of C opaifera langsdorffii Desf. under different water conditions

“…This result suggests that the plants showed very little reduction towards the critical limit, suggesting that they have some evolutionary characteristic to tolerate water shortage. According to the literature, F V /F M decreases under conditions of low water availability, leading to an increase in the photoinhibition processes (Lage-Pinto et al 2012).…”

Alteración De Los Recursos Naturales Y Su Efecto en El Paisaje en Zonas De Interés Turístico Al Sur De Chile

“…e Siparuna guianensis Aubl. sob três condições luminosas naturais: [1) sub-bosque de floresta natural, 2) sub-bosque de eucalipto sob regeneração e 3) sub-bosque de plantação de eucalipto com árvores de 18 anos que foram removidas um ano antes foi avaliada sob estações de seca e chuva(LAGE-PINTO et al, 2012). Esses autores observaram que, embora ambas espécies pertencem aos estágios iniciais de sucessão ecológica, apresentaram fotoinibição dinâmica após 1 ano de exposição a pleno sol em ambas as estações, acentuadamente na estação seca.…”