Effects of tree architecture on pollen dispersal and mating patterns in Abies pinsapo Boiss. (Pinaceae).

Plant architecture is crucial to pollination and mating in wind-pollinated species. We investigated the effect of crown architecture on pollen dispersal, mating system and offspring quality, combining phenotypic and genotypic analyses in a low-density population of the endangered species Abies pinsapo. A total of 598 embryos from three relative crown height levels (bottom, middle and top) in five mother plants were genotyped using eleven nuclear microsatellite markers (nSSRs). Paternity analysis and mating system models were used to infer mating and pollen dispersal parameters. In addition, seeds were weighed (N = 16 110) and germinated (N = 736), and seedling vigour was measured to assess inbreeding depression. Overall, A. pinsapo shows a fat-tailed dispersal kernel, with an average pollen dispersal distance of 113-227 m, an immigration rate of 0.84-26.92%, and a number of effective pollen donors (Nep ) ranging between 3.5 and 11.9. We found an effect of tree height and relative crown height levels on mating parameters. A higher proportion of seeds with embryo (about 50%) and a higher rate of self-fertilization (about 60%) were found at the bottom level in comparison with the top level. Seed weight and seedling vigour are positively related. Nevertheless, no differences were found in seed weight or in seedling-related variables such as weight and length of aerial and subterranean parts among the different relative crown height levels, suggesting that seeds from the more strongly inbred bottom level are not affected by inbreeding depression. Our results point to vertical isotropy for outcross-pollen and they suggest that self-pollen may ensure fertilization when outcross-pollen is not available in low-density population.

Phylogeography of SW Mediterranean firs: different European origins for the North African Abies species.

The current distribution of Western Mediterranean Abies species is a result of complex geodynamic processes and climatic oscillations that occurred in the past. Abies sect. Piceaster offers a good study model to explore how geo-climatic oscillations might have influenced its expansion and diversification on both sides of the W Mediterranean basin. We investigated the genetic variation within and among nine populations from five Abies species by molecular markers with high and low mutation rates and contrasting inheritance (AFLP and cpSSR). Analyses revealed the opening of the Strait of Gibraltar as an effective barrier against gene flow between the Southern Iberian (A. pinsapo) and North African (A. marocana and A. tazaotana) firs. The A. pinsapo populations in Spain and likewise those of the A. marocana - A. tazaotana population complex were not differentiated, and no evidence was found to distinguish A. tazaotana at the species level. Diversification of Abies across North Africa could occur by way of at least two vicariant events from Europe, in the west, giving rise to the A. marocana - A. tazaotana complex, and in the east, giving A. numidica. Secondary contacts among species from Abies sect. Piceaster (A. pinsapo and A. numidica), and with A. alba (Abies sect. Abies) are also indicated. However, there is a closer relationship between the Algerian fir (A. numidica) and the North Mediterranean widespread A. alba, than with the Moroccan firs (A. marocana and A. tazaotana) or the Southern Iberian (A. pinsapo). We also discuss the distribution range of these taxa in its paleogeological and paleoclimatic context, and propose that part of the modern geography of the South-Western Mediterranean firs might be traced back to the Tertiary.

Nuclear microsatellite primers for the endangered relict fir, Abies pinsapo (Pinaceae) and cross-amplification in related Mediterranean Species.

Twelve nuclear microsatellite primers (nSSR) were developed for the endangered species Abies pinsapo Boiss. to enable the study of gene flow and genetic structure in the remaining distribution areas. Microsatellite primers were developed using next-generation sequencing (454) data from a single Abies pinsapo individual. Primers were applied to thirty individuals from the three extant localities. The number of alleles per locus ranged from one to four. Cross-amplification was tested for other Abies species from the Mediterranean Basin, and most of the loci showed higher polymorphisms in the Mediterranean species than in A. pinsapo. These microsatellite markers provide tools for conservation genetic studies in Abies pinsapo as well other Abies species from the Mediterranean Basin.