J. L. F. Pires

Evaluation of genetic diversity of Portuguese Pinus sylvestris L. populations based on molecular data and inferences about the future use of this germplasm.

1Institute for Biotechnology and Bioengineering, Centre of Genomics and Biotechnology (IBB/CGB), 3Department of Forestry Sciences and Landscape (CIFAP), and 4Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tras-os-Montes and Alto Douro (UTAD), P.O. Box 1013, 5001-801 Vila Real, Portugal 2Centre of Forestry Studies (CEF), ISA, UTL Tapada da Ajuda, 1349-017 Lisbon, Portugal

Differential physiological and genetic responses of five European Scots pine provenances to induced water stress

Pinus sylvestris L. (Scots pine) is the conifer with widest natural distribution area. Portugal constitutes its westernmost limit of distribution. Most of the Portuguese populations were planted but two autochthonous populations were recently ascribed to Serra do Gerês (NW Portugal), and seem to be well adapted to the temperate climate. However, the ongoing climate changes may compromise their survival. With this study we intend to evaluate the anatomic-physiological and genetic responses of Scots pine from five European provenances (Gerês, Puebla de Lillo, Montes Universales, Germany and Sweden) to three water availability regimes, in order to determine which one(s) present higher resistance to drought. Individuals from Gerês presented the highest stability in photosynthetic reactions as well as the better photochemical and metabolic behaviours under drought (T3). Hence, the relative expression ratio of three water stress-responsive genes during drought was lower and gradual in Gerês, compared to all other provenances, followed by Germany. The results achieved in Gerês and Germany provenances are very interesting since they reflected that the native populations of Gerês along with the Portuguese Scots pine planted populations with a probable German provenance, have ability and high adaptive potential to respond to situations of water deficit. Moreover, the present genetic and physiological data demonstrated the urgent demand for the conservation of Portuguese Scots pine genetic resources as well as its use in plantation/afforestation of areas where the warming and drought has been affecting the survival of this species.

Within and between-tree variation of wood density components in Pinus sylvestris at five sites in Portugal

Pinus sylvestris is widely distributed in Europe and Asia, and Portugal constitutes its westernmost limit. The reduction of the Portuguese forest area of resinous species has provoked strong constraints on wood industries supply. Therefore, an increase in Scots pine area might be important, namely by reforestations of higher altitude areas, where Pinus pinaster has great difficulties to vegetate and where the risk of pinewood nematode attack is smaller. However, large gaps remain in the knowledge of Pinus sylvestris wood characteristics growing in Portugal. To address this question, the radial wood density and growth were evaluated by X-ray microdensitometric technique, sampling 100 adult trees from five representative sites of P. sylvestris distribution area in Portugal. The results revealed that Portuguese Pinus sylvestris shows good radial growth and denser wood than those found in northern European regions. Among the Portuguese stands, sites at a lower altitude (Gerês and Marão) exhibited denser wood. Regarding density components, it was verified that the differences among sites were more significant in latewood, while the differences between trees/sites were most expressive in earlywood. These facts induce a higher genetic control in earlywood characteristics and a greater dependence of latewood components on environmental and climatic effects. Regarding growth components, Trees and Rings effects were more noticeable than Site effect. Concerning radial patterns, Portuguese Pinus sylvestris shows a downward trend in the first years after the pith, followed by an increase in latter rings for the density traits, while the radial variation of ring width is expressed by a tendency of decrease from the pith to the cambium. Compared to other European regions, Portuguese Pinus sylvestris reveals good wood quality features, namely higher density and ring width values. However, compared to Portuguese Pinus pinaster it shows a relatively lower density and identical or relatively lower radial growth. Scots pine could be a good solution for future reforestations of Portuguese mountainous areas, less favorable to other species.

Within- and between-tree variation of wood density components in Pinus nigra at six sites in Portugal

Key messageIn Europe, P. nigrawood presents a density pattern of longitudinal variation with an increase from east to west. However, no latitudinal tendencies were detected. Compared to other Portuguese resinous species,P. nigrarevealed higher density, identical radial growth and intra-ring heterogeneity, which presents advantages for industry purposes. The environmental factors (Sites effect) manifest more strongly in the latewood components while the Trees/Sites effect is more strongly expressed in the earlywood components.ContextAlthough P. nigra Arnold is one of the most important conifers in Europe, little is known about the wood’s characteristics in the southwest European region.AimsOur aims are to outline a first approach to study the growth and wood quality in P. nigra in Portugal comparing to other European natural stands and other resinous species.MethodsInter- and intra-wood density variation of P. nigra from six Portuguese sites was studied using microdensitometry. Analysis of variance (ANOVA) was performed in three subsets: 50 common rings, core (juvenile wood) and peripheral analysis (mature wood).ResultsThe average ring density was 0.588xa0gxa0cm−3, with maximum values in the north and low altitudes. Regarding growth traits, no latitudinal and altitudinal tendencies were detected. Compared to the main timber species in Portugal (P. pinaster Aiton), P. nigra showed similar radial growth, higher density but lower intra-ring density homogeneity. The Sites effect mainly influenced latewood density components, while the Trees/Sites effect primarily influenced earlywood components. The Rings effect was found to be relatively low, with a density decrease in the tree’s first years followed by an increase in the periphery. Growth traits showed a reduction from pith to bark.ConclusionConsidering the quality (density) and growth features of the Black pine, this species could be useful for the reforestation of mountainous Southern Europe areas that are not favourable for other species.