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

Abstract

Myrcia amazonica DC. occurs in gallery forest and ''campo rupestre'' vegetation in the Chapada Diamantina, Bahia State, Brazil-habitats with contrasting irradiance and humidity conditions. We evaluated variations in aspects of the cost-benefit relationships of leaf maintenance and photosynthetic activity (phenology, leaf age, gas exchange, and photosynthetic pigments) and the maintenance of a positive water balance (leaf water potential, wood density, and leaf attributes) in two populations of M. amazonica occurring in those habitats. Our hypothesis was that this species would show more efficient water use associated with maintaining its leaves for longer periods in ''campo rupestre'' vegetation rather than in gallery forests-linked to the environmental constraints on ''campo rupestre'' population (lower water availability and elevated irradiance). We found that individuals growing in ''campo rupestre'' showed greater stomatal conductance, CO 2 assimilation, transpiration rates, leaf thicknesses, leaf succulence, daily water potential amplitudes, and leaf longevity but lower wood densities as compared to the gallery forest population. Even with wide contrasts in terms of all of these parameters, both populations maintained perennial leaf patterns, despite with variations in the intensities and durations of leaf production (being more intense and of shorter duration in the ''campo rupestre'' population). Myrcia amazonica demonstrated high functional and morphological plasticity of attributes related to its survival and growth in these habitats. Our hypothesis was confirmed, as ''campo rupestre'' plants showed morphofunctional strategies associated with resource conservation, including more efficient water use.

Leaf trait variability maintains similar leaf exchange rhythms in Hirtella glandulosa Spreng. (Chrysobalanaceae) populations growing on contrasting soil types in the Brazilian Atlantic Forest

“…Such variability has been widely discussed in ecology and emphasized in studies seeking to understand variations in niche breadth (Roughgarden 1972), individual specialization, and environmental heterogeneity (Bolnick 2003;Clark 2010), and intraspecific polymorphism (Pruitt and Ferrari 2011). Intraspecific variability in plants enables them to survive, grow, and reproduce under distinct environmental conditions (Albert et al 2010) and is especially linked to adjustments of traits associated with intrapopulational variations among many tropical trees, including those associated with seasonal variations, soil properties, and environmental gradients (Moraes et al 2017;Chacón-Madrigal et al 2018;Pireda et al 2019;Vitória et al 2019;Santos et al in press).…”

“…Certain leaf traits (such as leaf mass per area [LMA]) may vary due to water availability in the environment (Moraes et al 2017) and will tend to favor less negative leaf water potentials under drought regimes (Lamont and Lamont 2000;Rosado and de Mattos 2007). Increases in LMA under waterlimited regimes (Lamont and Lamont 2000;Rosado and de Mattos 2007) can lead to decreases in photosynthetic capacity (Kikuzawa and Lechowicz 2011).…”

“…Increases in LMA under waterlimited regimes (Lamont and Lamont 2000;Rosado and de Mattos 2007) can lead to decreases in photosynthetic capacity (Kikuzawa and Lechowicz 2011). As such, photosynthesis is a key aspect that may correlate with plant phenological stages (Ciganda et al 2008;Kikuzawa and Lechowicz 2011;Moraes et al 2017;Vitoria et al 2019), and LMA may provide important information about variations in a plant's physiological status in relation to water restrictions.…”

Seasonality and the Relationships Between Reproductive and Leaf Phenophases In Myrtaceae Using Field and Herbarium Data

“…As Myrtaceae is an important arboreal component of tropical forests, the phenology of the family has been the subject of several studies and evidenced flowering and fruiting seasonality (Staggemeier et al, 2010;2015;. Most species have been treated as evergreen, although leaf phenology and relationships between leaf and reproductive phenophases (Fonseca, 2008;Moraes et al, 2017) have received little attention.…”

“…desertorum and P. schenckianum -both more frequent in caatinga environments (Oliveira et al, 2012;Landrum, 2017), where seasonal water restrictions are strong drivers of plant ecological strategies (Neves et al, 2017). The field data of E. punicifolia reveals the initial development of young leaves, with flower bud development occurring slightly later (Moraes et al, 2017).…”