Micro-evolutionary patterns of juvenile wood density in a pine species

Abstract

Wood density can be considered an adaptive trait, because it ensures the safe and efficient transport of water from the roots to the leaves, mechanical support for the body of the plant and the storage of biological chemicals. Its variability has been extensively described in narrow genetic backgrounds and in wide ranges of forest tree species, but little is known about the extent of natural genetic and phenotypic variability within species. This information is essential to our understanding of the evolutionary forces that have shaped this trait, and for the evaluation of its inclusion in breeding programs. We assessed juvenile wood density, leaf area, total aboveground biomass, and growth in six Pinus pinaster populations of different geographic origins (France, Spain, and Morocco) growing in a provenance-progeny trial. No genetic differentiation was found for wood density, whereas all other traits significantly differed between populations. Heritability of this trait was moderate, with a low additive genetic variance. For retrospective identification of the evolutionary forces acting on juvenile wood density, we compared the distribution of neutral markers (F ST ) and quantitative genetic differentiation (Q ST ). We found that Q ST was significantly lower than F ST , suggesting evolutionary stasis. Furthermore, we did not detect any relationship between juvenile wood density and drought tolerance (resistance to cavitation), suggesting that this trait could not be used as a proxy for drought tolerance at the intraspecific level.

Climatic limits of temperate rainforest tree species are explained by xylem embolism resistance among angiosperms but not among conifers

“…Southern hemisphere conifers are known for their small tracheids (Pittermann et al , ) that are associated with slow growth rates and denser wood, which may also enhance their resistance to microbial decomposition in rainy environments (Boddy, ). Experimental nutrient additions reduced wood density and increased vulnerability to stem embolism in hybrid poplar saplings (Hacke et al , ), but other studies have shown that reduced wood density in response to increased nutrient availability does not necessarily lead to higher vulnerability (Bucci et al , ; Lamy et al , ; Goldstein et al , ). Future work should quantify embolism resistance in other more cavitation‐prone organs (leaves and roots) to determine whether these can shed additional light on these curious conifers.…”

Natural selection and neutral evolutionary processes contribute to genetic divergence in leaf traits across a precipitation gradient in the tropical oak Quercus oleoides

“…In a series of studies, Lamy et al. (), Lamy, Lagane, Plomion, Cochard, and Delzon (), Lamy et al. () found weak population divergence and significantly lower Q ST than F ST in Pinus pinaster for cavitation resistance and wood density, traits that are also associated with plant hydraulic conductance.…”

Intraspecific variation of anatomical and chemical defensive traits in Maritime pine (Pinus pinaster) as factors in susceptibility to the pinewood nematode (Bursaphelenchus xylophilus)

“…1), Maritime pine has a fragmented distribution, with numerous relatively small and isolated populations (Bucci et al 2007). Reduced gene flow among populations has favored a strong differentiation between them, which is well documented in terms of genetic (González-Martínez et al 2002;Burban and Petit 2003) and phenotypic variation of different adaptive traits (Chambel et al 2007;Corcuera et al 2012;Santos del Blanco et al 2012), other relevant traits for timber production (de la Mata and Zas 2010a; Lamy et al 2012), and herbivore and pathogen resistance (Arrabal et al 2005). For example, intraspecific variation in resin flux (Tadesse et al 2001 Trees polyphenols and condensed tannins in stems and needles , and resin terpene profiles (Arrabal et al 2005;Sampedro et al 2010) have all been reported.…”