Complex bioclimatic and soil gradients shape leaf trait variation in Embothrium coccineum (Proteaceae) among austral forests in Patagonia

Abstract

Patterns of trait variation may be adaptive when vary in relation to an environmental gradient. In particular, leaf traits can affect productivity and competitive ability. We identify patterns of leaf size and shape variation with environmental heterogeneity in one of the most widespread tree species within temperate South America: Embothrium coccineum (Proteaceae). We collected leaf specimens and composite soil samples from 35 populations between 38º and 55º S latitude in Patagonia, covering a wide range of mean annual precipitation (MAP) and mean annual temperature (MAT). At each location, we measured nine morphological traits, some of which were cross correlated hence we focus on a smaller number of representative traits. We hypothesized that leaf area (LA), dry mass (DM), and specific leaf area (SLA) would increase, and that leaf shape (SF) would be more elongated, with increasing temperature, precipitation, and soil nutrient availability. We also expected growing season climate to be more closely associated with leaf traits than mean annual metrics. We used bivariate and backward stepwise multiple regressions to analyse the dependence of morphological traits with climatic and edaphic metrics. LA and DM increased with increasing summer rainfall or winter temperature, as hypothesized. Opposite to our hypothesis, LA and DM decreased with increasing summer temperature suggesting that in terms of leaf size, E. coccineum may sense summer conditions largely as an increasing aridity stressful gradient. Surprisingly, SLA increased with increasingly warm or dry summers. SF was related positively to MAT and negatively to MAP, suggesting that under more benign western climate regimes E. coccineum leaves tend to be elongated. Across sites, LA and DM increased with soil organic carbon and available phosphorus, and decreased with soil nitrogen and exchangeable cations. The opposite pattern was observed for SLA. Biologically meaningful climate metrics and soil nutrient conditions are useful predictors for leaf size and structure in the widespread E. coccineum. The SLA patterns probably resulted from lower values in long lasting leaves, in addition to increasing soil nitrogen, so leaves in the south are thicker. Alternatively, it could be consequence from non-isometrical scaling of LA and DM, so larger leaves such as those under oceanic western climates have lower SLA. Patterns of multiple leaf trait variation along complex environmental gradients may become uncoupled from each other, differing from what is suggested in the literature for traits that vary along simple environmental gradients.

Variación en atributos anatómicos asociados a la conducción y almacenamiento de agua, en tres poblaciones de Maihuenia poeppigii (Otto ex Pfeiff.) K. Schum. (Cactaceae) en un gradiente altitudinal

“…Las variaciones de atributos funcionales a lo largo de gradientes de altitud ha sido abordada por una serie de estudios (Arnold & Mauseth 1999, Cavieres et al 2000, Cabrera 2002, Alberdi & Donoso 2004, Souto et al 2009). Las más estudiadas han sido las variaciones en los conductos xilemáticos (densidad, diámetro y conductividad hidráulica relativa de los vasos) (Mauseth 1999, Davis et al 1999, Arias & Terrazas 2001, Hacke & Sperry 2001, Ladjal et al 2005, en la altura (Cavieres et al 2000, Körner 2003, Falster & Westoby 2005, y en la suculencia de las plantas (Mauseth 1999(Mauseth , 2000(Mauseth , 2006 especialmente en especies que crecen en condiciones limitantes y/o a mayores altitudes (Körner 2003).…”

Relationships between leaf shape and climate in Rhododendron mucronulatum

“…As shown by Marcysiak (), the amount of precipitation during the growing season is positively correlated with leaf length. Furthermore, Souto et al () found that temperatures and precipitation during the growing season are much more important for the leaf formation than the same parameters during winter period. However, at the local scale (Primorsky Krai), we found that the synchronous increase of leaf length, width and area is highly correlated to precipitation seasonality (r 2 = 0.11, r 2 = 0.13 and r 2 = 0.12) and the amount of precipitation during the winter season (r 2 = 0.11, r 2 = 0.11 and r 2 = 0.10), although not as strongly as to the amount of precipitation during the growing season (r 2 = 0.06, r 2 = 0.14 and r 2 = 0.09).…”

“…Besides, mean annual temperature and precipitation determine the presence and prominence of leaves dissection (Peppe et al 2011). However, Souto et al (2009) showed that precipitation and temperature during the growing season have a greater influence on leaf parameters than do their annual averages. Precipitation is the most important factor during the growing season, and it is positively correlated with leaf length (Royer and Wilf 2006, Peppe et al 2011, Marcysiak 2013.…”

Role of transpiration in arsenic accumulation of hyperaccumulator Pteris vittata L.

“…The adaptation of leaf structure, morphologically or histologically, often reflects clearly the effect of environmental stress and therefore is often used as an index evaluating the impacts of environmental conditions on plants (Dinis et al 2011;Souto et al 2009). The significant interactive effect of ecotype and transpiration regulation (P<0.05) indicated that different ecotypes had varying responses to transpirationaltering measures.…”