Low but significant evolutionary potential for growth, phenology and reproduction traits in European beech.

Local survival of forest tree populations under climate change depends on existing genetic variation and their adaptability to changing environments. Responses to selection were studied in European beech (Fagus sylvatica) under field conditions. A total of 1087 adult trees, seeds, 1-year-old seedlings and established multiyear saplings were genotyped with 16 nuSSRs. Adult trees were assessed for phenotypic traits related to growth, phenology and reproduction. Parentage and paternity analyses were used to estimate effective female and male fecundity as a proxy of fitness and showed that few parents contributed to successful regeneration. Selection gradients were estimated from the relationship between traits and fecundity, while heritability and evolvability were estimated using mixed models and the breeder's equation. Larger trees bearing more fruit and early male flowering had higher total fecundity, while trees with longer growth season had lower total fecundity (directional selection). Stabilizing selection on spring phenology was found for female fecundity, highlighting the role of late frosts as a selection driver. Selection gradients for other traits varied between measurement years and the offspring cohort used to estimate parental fecundity. Compared to other studies in natural populations, we found low to moderate heritability and evolvability for most traits. Response to selection was higher for growth than for budburst, leaf senescence or reproduction traits, reflecting more consistent selection gradients across years and sex functions, and higher phenotypic variability in the population. Our study provides empirical evidence suggesting that populations of long-lived organisms such as forest trees can adapt locally, even at short-time scales.

Ectomycorrhizal community composition of organic and mineral soil horizons in silver fir (Abies alba Mill.) stands.

Vertical ectomycorrhizal (ECM) community composition was assessed on silver fir (Abies alba Mill.) in beech-silver fir forests in Bosnia and Herzegovina. Organic and upper mineral horizons were described by pedological analyses. Silver fir root tips were divided into vital ECM, old and non-mycorrhizal for each horizon separately. Morpho-anatomical classification of vital ECM root tips with an assessment of abundance was followed by ITS-based molecular characterization and classification into exploration types. The percentage of vital ECM root tips was not affected by the soil horizon. Altogether, 40 ECM taxa were recorded. Several taxa have not previously been reported for silver fir: Hebeloma laterinum, Inocybe fuscidula, I. glabripes, Lactarius acris, L. albocarneus, L. blennius, L. fluens, Ramaria bataillei, Russula badia, R. lutea, R. mairei, Sistotrema sp., Tarzetta catinus, Tomentella atroarenicolor, T. badia, T. cinerascens, T. bryophylla, and T. ramosissima, indicating high potential for diversity of ECM fungi in silver fir stands. No significant differences in community composition and species richness and diversity were detected between mineral and organic horizons. Community composition was affected by CaCO3, organic carbon concentration, organic carbon stock, total nitrogen stock, C/N ratio and soil bulk density. No significant effects of soil parameters were detected for exploration types. The contact exploration type was dominant in both soil horizons. Significantly different relative abundances of dominant taxa Tomentella stuposa, Cenococcum geophilum and Piloderma sp. 1 were detected in the two horizons. Twelve taxa were limited to the organic horizon and eight to the mineral horizon.

Scleroderma areolatum ectomycorrhiza on Fagus sylvatica L.

Despite its broad host range and distribution and its potential applications in commercial plantation forests, comprehensive descriptions of Scleroderma ectomycorrhizae are available only for Scleroderma citrinum, Scleroderma bovista and Scleroderma sinnamariense. This study provides a morphological and anatomical description of tree nursery derived ectomycorrhizae of Scleroderma areolatum on Fagus sylvatica, grown for several years in a climatized room. Ectomycorrhizae of S. areolatum were silvery white with abundant rhizomorphs; all mantle layers were plectenchymatous, rhizomorphs of type E, with prominent emanating hyphae with thick cell wall. The distal ends of emanating hyphae of rhizomorphs were inflated and often merged with other emanating hyphae. All parts of the mycorrhiza were clampless. In hyphae of the outer mantle layer, rhizomorphs and emanating hyphae, oily droplets were observed that did not stain in sulfo-vanillin and disappeared in lactic acid after a few hours. Although the phylogenetic analysis positioned the newly described ectomycorrhiza together with Scleroderma verrucosum and Scleroderma cepa in a single clade with a taxon name SH005470.07FU, the ectomycorrhizae of these three species can be morphologically well separated based on rhizomorph type.

Forest genetic monitoring: an overview of concepts and definitions.

Safeguarding sustainability of forest ecosystems with their habitat variability and all their functions is of highest priority. Therefore, the long-term adaptability of forest ecosystems to a changing environment must be secured, e.g., through sustainable forest management. High adaptability is based on biological variation starting at the genetic level. Thus, the ultimate goal of the Convention on Biological Diversity (CBD) to halt the ongoing erosion of biological variation is of utmost importance for forest ecosystem functioning and sustainability. Monitoring of biological diversity over time is needed to detect changes that threaten these biological resources. Genetic variation, as an integral part of biological diversity, needs special attention, and its monitoring can ensure its effective conservation. We compare forest genetic monitoring to other biodiversity monitoring concepts. Forest genetic monitoring (FGM) enables early detection of potentially harmful changes of forest adaptability before these appear at higher biodiversity levels (e.g., species or ecosystem diversity) and can improve the sustainability of applied forest management practices and direct further research. Theoretical genetic monitoring concepts developed up to now need to be evaluated before being implemented on a national and international scale. This article provides an overview of FGM concepts and definitions, discusses their advantages and disadvantages, and provides a flow chart of the steps needed for the optimization and implementation of FGM. FGM is an important module of biodiversity monitoring, and we define an effective FGM scheme as consisting of an assessment of a forest population's capacity to survive, reproduce, and persist under rapid environmental changes on a long-term scale.

Vulnerability of dynamic genetic conservation units of forest trees in Europe to climate change.

A transnational network of genetic conservation units for forest trees was recently documented in Europe aiming at the conservation of evolutionary processes and the adaptive potential of natural or man-made tree populations. In this study, we quantified the vulnerability of individual conservation units and the whole network to climate change using climate favourability models and the estimated velocity of climate change. Compared to the overall climate niche of the analysed target species populations at the warm and dry end of the species niche are underrepresented in the network. However, by 2100, target species in 33-65 % of conservation units, mostly located in southern Europe, will be at the limit or outside the species' current climatic niche as demonstrated by favourabilities below required model sensitivities of 95%. The highest average decrease in favourabilities throughout the network can be expected for coniferous trees although they are mainly occurring within units in mountainous landscapes for which we estimated lower velocities of change. Generally, the species-specific estimates of favourabilities showed only low correlations to the velocity of climate change in individual units, indicating that both vulnerability measures should be considered for climate risk analysis. The variation in favourabilities among target species within the same conservation units is expected to increase with climate change and will likely require a prioritization among co-occurring species. The present results suggest that there is a strong need to intensify monitoring efforts and to develop additional conservation measures for populations in the most vulnerable units. Also, our results call for continued transnational actions for genetic conservation of European forest trees, including the establishment of dynamic conservation populations outside the current species distribution ranges within European assisted migration schemes.

Biogeography of ectomycorrhizal fungi associated with alders (Alnus spp.) in relation to biotic and abiotic variables at the global scale.

· Much of the macroecological information about microorganisms is confounded by the lack of standardized methodology, paucity of metadata and sampling effect of a particular substrate or interacting host taxa. · This study aims to disentangle the relative effects of biological, geographical and edaphic variables on the distribution of Alnus-associated ectomycorrhizal (ECM) fungi at the global scale by using comparable sampling and analysis methods. · Ribosomal DNA sequence analysis revealed 146 taxa of ECM fungi from 22 Alnus species across 96 sites worldwide. Use of spatial and phylogenetic eigenvectors along with environmental variables in model selection indicated that phylogenetic relations among host plants and geographical links explained 43 and 10%, respectively,in ECM fungal community composition, whereas soil calcium concentration positively influenced taxonomic richness. · Intrageneric phylogenetic relations among host plants and regional processes largely account for the global biogeographic distribution of Alnus-associated ECM fungi. The biogeography of ECM fungi is consistent with ancient host migration patterns from Eurasia to North America and from southern Europe to northern Europe after the last glacial maximum, indicating codispersal of hosts and their mycobionts.

Dynamic conservation of forest genetic resources in 33 European countries.

Dynamic conservation of forest genetic resources (FGR) means maintaining the genetic diversity of trees within an evolutionary process and allowing generation turnover in the forest. We assessed the network of forests areas managed for the dynamic conservation of FGR (conservation units) across Europe (33 countries). On the basis of information available in the European Information System on FGR (EUFGIS Portal), species distribution maps, and environmental stratification of the continent, we developed ecogeographic indicators, a marginality index, and demographic indicators to assess and monitor forest conservation efforts. The pan-European network has 1967 conservation units, 2737 populations of target trees, and 86 species of target trees. We detected a poor coincidence between FGR conservation and other biodiversity conservation objectives within this network. We identified 2 complementary strategies: a species-oriented strategy in which national conservation networks are specifically designed for key target species and a site-oriented strategy in which multiple-target units include so-called secondary species conserved within a few sites. The network is highly unbalanced in terms of species representation, and 7 key target species are conserved in 60% of the conservation units. We performed specific gap analyses for 11 tree species, including assessment of ecogeographic, demographic, and genetic criteria. For each species, we identified gaps, particularly in the marginal parts of their distribution range, and found multiple redundant conservation units in other areas. The Mediterranean forests and to a lesser extent the boreal forests are underrepresented. Monitoring the conservation efficiency of each unit remains challenging; however, <2% of the conserved populations seem to be at risk of extinction. On the basis of our results, we recommend combining species-oriented and site-oriented strategies.

Effect of earthworms on mycorrhization, root morphology and biomass of silver fir seedlings inoculated with black summer truffle (Tuber aestivum Vittad.).

Species of the genus Tuber have gained a lot of attention in recent decades due to their aromatic hypogenous fruitbodies, which can bring high prices on the market. The tendency in truffle production is to infect oak, hazel, beech, etc. in greenhouse conditions. We aimed to show whether silver fir (Abies alba Mill.) can be an appropriate host partner for commercial mycorrhization with truffles, and how earthworms in the inoculation substrate would affect the mycorrhization dynamics. Silver fir seedlings inoculated with Tuber. aestivum were analyzed for root system parameters and mycorrhization, how earthworms affect the bare root system, and if mycorrhization parameters change when earthworms are added to the inoculation substrate. Seedlings were analyzed 6 and 12 months after spore inoculation. Mycorrhization with or without earthworms revealed contrasting effects on fine root biomass and morphology of silver fir seedlings. Only a few of the assessed fine root parameters showed statistically significant response, namely higher fine root biomass and fine root tip density in inoculated seedlings without earthworms 6 months after inoculation, lower fine root tip density when earthworms were added, the specific root tip density increased in inoculated seedlings without earthworms 12 months after inoculation, and general negative effect of earthworm on branching density. Silver fir was confirmed as a suitable host partner for commercial mycorrhization with truffles, with 6% and 35% mycorrhization 6 months after inoculation and between 36% and 55% mycorrhization 12 months after inoculation. The effect of earthworms on mycorrhization of silver fir with Tuber aestivum was positive only after 6 months of mycorrhization, while this effect disappeared and turned insignificantly negative after 12 months due to the secondary effect of grazing on ectomycorrhizal root tips.

Root-Associated Fungal Communities From Two Phenologically Contrasting Silver Fir (Abies alba Mill.) Groups of Trees.

Root-associated fungal communities are important components in ecosystem processes, impacting plant growth and vigor by influencing the quality, direction, and flow of nutrients and water between plants and fungi. Linkages of plant phenological characteristics with belowground root-associated fungal communities have rarely been investigated, and thus our aim was to search for an interplay between contrasting phenology of host ectomycorrhizal trees from the same location and root-associated fungal communities (ectomycorrhizal, endophytic, saprotrophic and pathogenic root-associated fungi) in young and in adult silver fir trees. The study was performed in a managed silver fir forest site. Twenty-four soil samples collected under two phenologically contrasting silver fir groups were analyzed for differences in root-associated fungal communities using Illumina sequencing of a total root-associated fungal community. Significant differences in beta diversity and in mean alpha diversity were confirmed for overall community of ectomycorrhizal root-associated fungi, whereas for ecologically different non-ectomycorrhizal root-associated fungal communities the differences were significant only for beta diversity and not for mean alpha diversity. At genus level root-associated fungal communities differed significantly between early and late flushing young and adult silver fir trees. We discuss the interactions through which the phenology of host plants either drives or is driven by the root-associated fungal communities in conditions of a sustainably co-naturally managed silver fir forest.

Abscisic acid enhances lead translocation from the roots to the leaves and alleviates its toxicity in Populus × canescens.

To shed light on physiological mechanisms underlying abscisic-acid (ABA)-mediated lead (Pb) uptake, translocation and detoxification, we exposed Populus × canescens saplings to either 0 or 3 mM Pb2+ in combination with either 0 or 10 µM exogenous ABA. Pb was taken up by the roots and accumulated mainly in the cortex. A fraction of the Pb in the roots was translocated to the leaves, thereby resulting in decreased photosynthesis and biomass. Pb accumulation caused a burst of reactive oxygen species (ROS), with higher concentrations of total thiols, glutathione, and ascorbate in the roots and/or leaves. Exogenous ABA stimulated Pb uptake, decreased Pb deposition in the cortex, and enhanced Pb vascular loading in the roots. Exogenous ABA alleviated the Pb-induced reductions in photosynthesis and root biomass, and decreased Pb-triggered ROS overproduction in the roots and/or leaves. Correspondingly, exogenous ABA stimulated the mRNA levels of a few genes involved in Pb uptake, transport, and detoxification, including NRAMP1.4, ABCG40, FRD3.1, PCS1.1, and ABCC1.1. These results suggest that exogenous ABA enhances Pb uptake and translocation, and alleviates Pb toxicity in poplars through the ABA-induced movement of Pb from the root cortex to the vascular stele, and transcriptionally regulated key genes involved in Pb tolerance.

Different belowground responses to elevated ozone and soil water deficit in three European oak species (Quercus ilex, Q. pubescens and Q. robur).

Effects on roots due to ozone and/or soil water deficit often occur through diminished belowground allocation of carbon. Responses of root biomass, morphology, anatomy and ectomycorrhizal communities were investigated in seedlings of three oak species: Quercus ilex L., Q. pubescens Willd. and Q. robur L., exposed to combined effects of elevated ozone (ambient air and 1.4 × ambient air) and water deficit (100% and 10% irrigation relative to field capacity) for one growing season at a free-air ozone exposure facility. Effects on root biomass were observed as general reduction in coarse root biomass by -26.8% and in fine root biomass by -13.1% due to water deficit. Effect on coarse root biomass was the most prominent in Q. robur (-36.3%). Root morphological changes manifested as changes in proportions of fine root (<2 mm) diameter classes due to ozone and water deficit in Q. pubescens and due to water deficit in Q. robur. In addition, reduced fine root diameter (-8.49%) in Q. robur was observed under water deficit. Changes in root anatomy were observed as increased vessel density (+18.5%) due to ozone in all three species, as reduced vessel tangential diameter (-46.7%) in Q. ilex due to interaction of ozone and water, and as generally increased bark to secondary xylem ratio (+47.0%) due to interaction of ozone and water. Water deficit influenced occurrence of distinct growth ring boundaries in roots of Q. ilex and Q. robur. It shifted the ectomycorrhizal community towards dominance of stress-resistant species, with reduced relative abundance of Tomentella sp. 2 and increased relative abundances of Sphaerosporella brunnea and Thelephora sp. Our results provide evidence that expression of stress effects varies between root traits; therefore the combined analysis of root traits is necessary to obtain a complete picture of belowground responses.

Characterization of natural habitats and diversity of Libyan desert truffles.

Desert truffles have traditionally been used as food in Libya. Desert truffle grows and gives fruit sporadically when adequate and properly distributed rainfall occurs with existence of suitable soil and mycorrhizal host plant. The present study aimed to identify and characterize two kinds of wild desert truffles from ecological and nutritional points that were collected from the studied area. The truffle samples were identified as Terfezia (known as red or black truffle) and Tirmania (known as white truffle). The nutritional values (protein, lipid and carbohydrate) of both Libyan wild truffle (Terfezia and Tirmania) were determined on a dry weight basis and result showed that Tirmania and Terfezia contained 16.3 and 18.5% protein, 6.2 and 5.9% lipid, 67.2 and 65% carbohydrate, respectively, in ascocarp biomass. The soil pH of the upper and lower regions of the Hamada Al-Hamra ranged between 8.2 and 8.5 giving suitable conditions for fructification. The plants, Helianthemum kahiricum and Helianthemum lippii were the dominant plants in Hamada Al-Hamra region found to form a mycorrhiza with desert truffles. The phylogenetic analysis of the genomic rDNA ITS region showed that, out of five collections three represented Tirmania pinoyi (Maire) Malencon, one Tirmania nivea (Desf.) Trappe, and one Terfezia boudieri Chatin.

Bacterial endophytes from seeds of Norway spruce (Picea abies L. Karst).

Endophytic bacteria from wooden plants and especially seed-associated endophytes are not well studied. Fresh seeds collected from four Norway spruce trees (Picea abies) from different locations in the Slovene subalpine region were surface-sterilised and dissected into a seed coat, embryo and endosperm. The presence of endophytes was detected by culturing methods and by direct amplification of the eubacterial 16S rDNA gene. Both approaches identified bacteria from genera Pseudomonas and Rahnella in the Norway spruce seeds. Both are known plant-associated bacteria with growth-promoting properties and biological control potential. We suggest that plant seeds could serve as a vector for transmission of beneficial bacteria.

Genetic differentiation of the Western Capercaillie highlights the importance of South-eastern Europe for understanding the species phylogeography.

The Western Capercaillie (Tetrao urogallus L.) is a grouse species of open boreal or high altitude forests of Eurasia. It is endangered throughout most mountain range habitat areas in Europe. Two major genetically identifiable lineages of Western Capercaillie have been described to date: the southern lineage at the species' southernmost range of distribution in Europe, and the boreal lineage. We address the question of genetic differentiation of capercaillie populations from the Rhodope and Rila Mountains in Bulgaria, across the Dinaric Mountains to the Slovenian Alps. The two lineages' contact zone and resulting conservation strategies in this so-far understudied area of distribution have not been previously determined. The results of analysis of mitochondrial DNA control region sequences of 319 samples from the studied populations show that Alpine populations were composed exclusively of boreal lineage; Dinaric populations of both, but predominantly (96%) of boreal lineage; and Rhodope-Rila populations predominantly (>90%) of southern lineage individuals. The Bulgarian mountains were identified as the core area of the southern lineage, and the Dinaric Mountains as the western contact zone between both lineages in the Balkans. Bulgarian populations appeared genetically distinct from Alpine and Dinaric populations and exhibited characteristics of a long-term stationary population, suggesting that they should be considered as a glacial relict and probably a distinct subspecies. Although all of the studied populations suffered a decline in the past, the significantly lower level of genetic diversity when compared with the neighbouring Alpine and Bulgarian populations suggests that the isolated Dinaric capercaillie is particularly vulnerable to continuing population decline. The results are discussed in the context of conservation of the species in the Balkans, its principal threats and legal protection status. Potential conservation strategies should consider the existence of the two lineages and their vulnerable Dinaric contact zone and support the specificities of the populations.

Influence of Pleurotus ostreatus inoculation on wood degradation and fungal colonization.

The influence of Pleurotus ostreatus inoculation on wood degradation and on fungal community structure was studied. The experiments were performed on an organically poor fly ash deposit covered with a 10 cm layer of beech wood chips inoculated with P. ostreatus isolate ZIM76. Compared to non-inoculated wood chips, inoculation increased the temperatures and relative humidities and, in the first 6 months, accelerated Klason lignin degradation by 9% and also, after 17 months, increased iron translocation into wood chips by 30%. After 6 months, PCR-DGGE showed 22-28 and 13-21 fungal taxa in non-inoculated and P. ostreatus-inoculated beech chips, respectively. The differences in number of taxa and in the fungal community structure (based on Dice coefficient) between non-inoculated and inoculated wood chips diminished with time. The results indicate that the naturally occurring processes of wood degradation are as efficient as those occurring in sites inoculated with P. ostreatus.

Types of ectomycorrhiza of mature beech and spruce at ozone-fumigated and control forest plots.

In the Kranzberg forest near Freising (Germany) a novel "Free-Air Canopy O3 Exposure" system has been employed for analysing O3-induced responses from sub-cellular to ecosystem levels that are relevant for carbon balance and CO2 demand of 60-year-old beech trees. The below-ground ectomycorrhizal community was studied in two-fold ambient O3 concentrations (five cores per sampling) and in a control plot with an ambient O3 concentration (four cores per sampling). Five samplings were taken throughout two vegetation seasons (2003 and 2004). Types of ectomycorrhiza were determined by their morphological, anatomical and molecular characteristics and quantified by counting. The total number of mycorrhizal fine roots was higher at the fumigated plot as compared with the control site. The numbers of ectomycorrhizal types at the fumigated and control plots were 28 and 26, respectively. Cenococcum geophilum was present in all soil cores at all sampling times with a significant increase in abundance under ozone-fumigated trees. Other mycorrhizal types present at higher abundance at the fumigated than at the control plot were identified as Russula densiflora, R. fellea, R. illota, Tuber puberulum, Lactarius sp. 2 and Russula sp. 2. Some mycorrhizal types were present exclusively at the fumigated plot (Fagirhiza fusca, F. setifera, Lactarius acris, Piceirhiza nigra and Russula sp. 1). A possible ecological role for the abundant types of ectomycorrhiza and their putative application in bio-indication is discussed.

Types of ectomycorrhiza as pollution stress indicators: case studies in Slovenia.

Mycorrhiza is the main spatial and temporal linkage between different constituents in a forest ecosystem. The functional compatibility and stress tolerance of ectomycorrhizal types is species specific, and therefore the information on the ectomycorrhizal community structure can add to the understanding of processes in forest ecosystems and can also be applied as tools for bioindication of pollution stress in forest soils. We have studied the effects of pollution (N and S) on trees and forest soils by: (1) quantification of ECM types diversity as in situ indicators in forest stands, (2) determination and quantification of pollution-sensitive or -insensitive ECM types as passive monitors, (3) root growth and development of ECM on nonmycorrhizal spruce seedlings, planted at the studied sites (active monitors), and (4) ECM infection (a bioassay based on mycorrhizal inoculum potential) of seedlings in an experimental set-up as ex situ testers. ECM species richness for Norway spruce trees (Picea abies) showed higher values in unpolluted sites than in polluted ones, while the differences were not significant for European beech trees (Fagus sylvatica). As pollution-sensitive or -insensitive ECM species in spruce forests, we suggest Hydnum rufescens (sensitive) and Paxillus involutus (unsensitive). Mycorrhizal potential in Norway spruce seedlings as a bioassay for soil N and S pollution was effective, and is suggested as an additional, standardized and widely comparable system in bioindication of soil pollution.