Stem radial increment of forest and savanna ecotypes of a Neotropical tree: relationships with climate, phenology, and water potential

Abstract

The aim of the present study was to investigate differences in stem radial increment between the savanna and forest ecotypes of Plathymenia reticulata at an ecotonal site. It was hypothesised that even under similar climate conditions, the savanna and forest ecotypes exhibit differences in radial growth, phenology, and water status because of differences in wood density. Stem radial increment, phenology, and water potential were evaluated monthly. The radial increment was positively related to precipitation and displayed no increment (or decrement) in months with low rainfall. A negative relationship was observed between radial growth and wood density, with the forest ecotype exhibiting a higher radial increment than the savanna ecotype. Midday water potential (W MD ) was also negatively related to wood density. Compared to the forest ecotype, the savanna ecotype displayed lower values of W MD during the dry season and started leaf senescence earlier at the beginning of the dry season. Leaf fall improved water status, resulting in leaf flushing even without a significant increase in rainfall. Radial growth significantly increased only after the crown leaf cover was completed. The results confirmed the importance of wood density in the differential responses of ecotypes in relation to growth, water status, and phenology.

Leaf phenology and morphofunctional variation in Myrcia amazonica DC. (Myrtaceae) in gallery forest and “campo rupestre” vegetation in the Chapada Diamantina, Brazil

“…Our results indicate the existence of significant functional and structural plasticity in M. amazonica. Phenotypic plasticity has been observed in different populations of a single species, reflecting adaptations to diverse microclimates in a series of habitats (Abbruzzese et al 2009), as well as in different populations exposed to variations in irradiance in open or shaded habitats (even under otherwise similar climatic conditions) (Toledo et al 2012;Valladares and Niinemets 2008;Vieira et al 2015;Vitória et al 2016). The phenotypic plasticity index (PPI) has been Fig.…”

“…Studies focusing on variations in the physiological attributes of plants according to environmental conditions have been performed with a number of species (Boardman 1977;Chazdon 1986;Chen and Klinka 1997;Murchie and Horton 1997;Naramoto et al 2006;Sinclair et al 2008;Rodríguez-Garcia and Bravo 2013;Rossatto et al 2013;Puglielli et al 2015;Vieira et al 2015;Vitória et al 2016) and have demonstrated that populations established in environments with high solar irradiation have thicker leaves, with higher rates of gas exchange. Studies of morphofunctional traits have examined leaf renewal, leaf age, and wood density associated with habitat heterogeneity (Goulart et al 2005;Lemos Filho et al 2008;Toledo et al 2012;Capuzzo et al 2012). Attributes such as phenology, leaf age, gas exchange, photosynthetic pigments, water potential, wood density, and leaf morphological attributes (thicknesses, succulence, density, and leaf mass per area) have been correlated with environmental conditions such as irradiance, VPD, and water balance (Rosado and de Mattos 2007;Meinzer et al 2009;Rosado et al 2013;Rossatto et al 2013;Braga et al 2016).…”

Climatic drivers of leaf traits and genetic divergence in the tree Annona crassiflora: a broad spatial survey in the Brazilian savannas

“…Knowledge of the intraspecific variation in functional traits is important for evaluating the response of a species to climatic gradients, and for predicting how a species will respond to climate change (Jung et al, 2014). Environmental adaptation can be inferred from associations of intraspecific phenotypic variation with environmental gradients, especially in plants that occur across a wide range of conditions (Gonz alez-Rodr ıguez & Oyama, 2005;Goulart et al, 2006Goulart et al, , 2011Nakazato et al, 2008;Toledo et al, 2012); although associations without other lines of evidence should be subjected to further investigation before definitively concluding that they represent adaptations (Gould & Lewontin, 1979). Several studies have, in fact, shown changes in leaf traits along climatic gradients in various ecosystems (H odar, 2002;Reich et al, 2003;Gonz alez-Rodr ıguez & Oyama, 2005;Uribe-Salas et al, 2008;Poorter et al, 2009;Neffa, 2010;Spasojevic et al, 2014).…”

Geographical variation and the role of climate in leaf traits of a relict tree species across its distribution in China

“…Thus, quantifying intraspecific trait variation along environmental gradients, especially for plants with a wide distribution, is crucial for advancing our understanding of environmental effects on trait variation and for predicting species responses to climate change (González‐Rodríguez & Oyama ; Toledo et al . ; Zhou et al . ; Jung et al .…”