Growth, leaf and stomatal traits of crabwood (Carapa guianensis Aubl.) in central Amazonia

Abstract

-Crabwood (Carapa guianensis Aubl.) is a fast growing tree species with many uses among Amazonian local communities. The main objective of this study was to assess the effect of seasonal rainfall pattern on growth rates, and seasonal and diurnal changes in leaf gas exchange and leaf water potential (Ψ L ) in crabwood. To assess the effect of rainfall seasonality on growth and physiological leaf traits an experiment was conducted in Manaus, AM (03° 05´ 30" S, 59° 59´ 35" S). In this experiment, six 6-m tall plants were used to assess photosynthetic traits and Ψ L . In a second experiment the effect of growth irradiance on stomatal density (S D ), size (S S ) and leaf thickness was assessed in 0.8-m tall saplings. Stomatal conductance (g s ) and light-saturated photosynthesis (A max ) were higher in the wet season, and between 09:00 and 15:00 h. However, no effect of rainfall seasonality was found on Ψ L and potential photosynthesis (CO 2 -saturated). Ψ L declined from -0.3 MPa early in the morning to -0.75 MPa after midday. It increased in the afternoon but did not reach full recovery at sunset. Growth rates of crabwood were high, and similar in both seasons (2 mm month -1 ). Leaf thickness and S D were 19% and 47% higher in sun than in shade plants, whereas the opposite was true for S S . We conclude that Ψ L greatly affects carbon assimilation of crabwood by reducing g s at noon, although this effect is not reflected on growth rates indicating that other factors offset the effect of g s on A max .Keywords: Photosynthesis, Stomatal density, Crabwood and Amazonia. CRESCIMENTO, CARACTERÍSTICAS FOLIARES E ESTOMÁTICAS

Leaf phenology, growth and photosynthesis in Pseudobombax munguba (Malvaceae)

“…This shows that munguba could be better adapted to sunny environments, as suggested by Lorenzi (2009), who describes this species as heliophyte and pioneer. P Nsat values recorded in fully expanded leaves are within the range of values found in saplings of other Amazonian trees, such as Carapa guianensis, 8.97 µmol m -2 s -1 (Camargo & Marenco, 2012) and Garcinia brasiliensis, 7.53 µmol m -2 s -1 (Gouvêa & Marenco, 2018). Although the P Nsat values are within the expected rates for tree species, this assimilation rates did not lead to high RGR, which suggests the actual photosynthetic rate in the greenhouse was well below the values recorded under light saturated conditions.…”

“…Munguba tree grew about 1.9 mm per month in diameter and 15 cm month -1 in height, which is higher than growth rates (in diameter) observed in andiroba (Carapa spp) under greenhouse conditions, 0.9 mm month -1 (Oliveira & Marenco, 2019). However, this growth rates is similar to that reported by Camargo & Marenco (2012) in andiroba in the open, 1.9 -2.0 mm month -1 (in diameter). The RGR found in munguba (0.0105 g g -1 day -1 ) is lower than the RGR (0.04 -0.041 g g -1 day -1 ) reported by Shipley (2006) and Antúnez et al (2001) for other woody plants.…”

Fisiologia de espécies florestais da Amazônia: fotossíntese, respiração e relações hídricas

“…Em condição de alta irradiância a fixação de CO 2 do ecossistema varia entre 16 e 25 µmol m -2 s -1 (Malhi et al, 1998;Goulden et al, 2004). Além da irradiância, outros fatores que influenciam no padrão diurno da fotossíntese e condutância dos estômatos incluem variações diurnas no potencial hídrico (Ψ) da folha Camargo & Marenco, 2012), temperatura (Tribuzy, 2005) e DPV (Figura 7).…”

Ocorrência de Hypsipyla grandella Zeller (Lepidoptera, Pyralidae) no Sul do Estado de Roraima

“…A andiroba ainda tem sido apontada como uma espécie de potencial promissor para se aclimatar às mudanças ambientais previstas em futuro próximo para a maior parte da região amazônica (camargo & mareNco 2012). Podendo ser utilizada para enriquecer capoeiras, florestas, sistemas agroflorestais, bem como, na recuperação de áreas úmidas degradadas (Ferraz et al 2002;coNdé et al 2013).…”