Genetic Variation of Drought Tolerance in Pinus pinaster at Three Hierarchical Levels: A Comparison of Induced Osmotic Stress and Field Testing

Abstract

Understanding the survival capacity of forest trees to periods of severe water stress could improve knowledge of the adaptive potential of different species under future climatic scenarios. In long lived organisms, like forest trees, the combination of induced osmotic stress treatments and field testing can elucidate the role of drought tolerance during the early stages of establishment, the most critical in the life of the species. We performed a Polyethylene glycol-osmotic induced stress experiment and evaluated two common garden experiments (xeric and mesic sites) to test for survival and growth of a wide range clonal collection of Maritime pine. This study demonstrates the importance of additive vs non additive effects for drought tolerance traits in Pinus pinaster, and shows differences in parameters determining the adaptive trajectories of populations and family and clones within populations. The results show that osmotic adjustment plays an important role in population variation, while biomass allocation and hydric content greatly influence survival at population level. Survival in the induced osmotic stress experiment presented significant correlations with survival in the xeric site, and height growth at the mesic site, at population level, indicating constraints of adaptation for those traits, while at the within population level no significant correlation existed. These results demonstrate that population differentiation and within population genetic variation for drought tolerance follow different patterns.

High rate of adaptive evolution in two widespread European pines

“…Given the large differences between Scots pine and maritime pine with respect to their climatic niches, we focused on genes for general responses to different types of abiotic stresses. This is also consistent with previous studies ranking the importance of different fitness-related traits for local adaptation in the species (for Scots pine, see Castro, Zamora, H odar, & G omez, 2002;Galiano, Mart ınez-Vilalta, & Lloret, 2010;Ryypp€ o, Iivonen, Rikala, Sutinen, & Vapaavuori, 1998; and for maritime pine see Corcuera, Gil-Pelegrin, & Notivol, 2011;Gaspar, Velasco, Feito, Al ıa, & Majada, 2013;Lamy et al, 2014;Ram ırez-Valiente & Robledo-Arnuncio, 2014). Then, we used complementary methods to get insights into the action of selective forces, both at specific genes and at genomewide and considered the specific demographic, ecological and historical settings of each species to discuss the possible factors (both methodological and biological) that may explain our results.…”

Exploring natural variation ofPinus pinasterAiton using metabolomics: Is it possible to identify the region of origin of a pine from its metabolites?

“…These data are in agreement with the observations of Gaspar et al . () who showed significant differences (α<0.0001) in the survival rates between the provenances from Atlantic and Mediterranean regions in PEG‐induced osmotic stress experiments. Additional genetic studies by chloroplast microsatellite markers (Fig.…”

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

“…(Fernandes and Rigolot 2007), drought tolerance (Gaspar et al 2013) and cold tolerance (Prada et al 2014). Based on the relationships between the phenotypic expression of these traits and the environmental conditions in the place of origin, it has been inferred that the differentiation among provenances could be related to adaptive processes.…”