On variation, inheritance and chemical interrelationships of monoterpenes in scots pine (Pinus silvestris L.).
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Chromatography, Gas↗
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[The characteristics of the protein composition of the anomalous needles of spruce (Picea abies) and pine (Pinus silvestris) from the 10-kilometer zone of the Chernobyl Atomic Electric Power Station].
Comparative analysis for different antibodies' binding sites at the proteins samples, which were isolated from control and morphologically abnormal coniferous plants tissues have been investigated. Monoclonal antibodies against cytoskeletal proteins (actin, alpha- and beta tubulin), hsp 70 and against phosphotyrosine were used. It was detected that investigated biochemical features reflect morphological similarities between different plant species. Some differences between cytoskeleton proteins content in control and abnormal tissues have been also indicated. It is assumed that abnormal morphogenesis may be determined by low-level chronic irradiation during plants growth and development.
Electrophoresis, Polyacrylamide Gel↗
Identification and characterization of RAPD markers inferring genetic relationships among Pine species.
Total genomic DNAs were extracted from several populations of pine species and amplified using oligonucleotides of random sequences. Polymorphism in random amplified polymorphic DNA (RAPD) markers was high and sufficient in distinguishing each of the species. Genetic relationships among eight pine species (Pinus sylvestris, Pinus strobus, Pinus rigida, Pinus resinosa, Pinus nigra, Pinus contorta, Pinus monticola, and Pinus banksiana) from different provenances were analyzed. The degree of band sharing was used to evaluate genetic distance between species and to construct a phylogenetic tree. In general, the dendrogram corroborated the description of relationships based on morphological characteristics and crossability, but also provided new insights into pine taxonomy. RAPD markers specific to some pine species were cloned and sequenced. PCR amplifications using pairs of designed specific primers revealed that all the cloned sequences were likely genus specific because they were not found in spruce or larch. True species-specific sequences were identified using designed primers flanking cloned RAPD fragments. The analysis of RAPD fragment sequences confirmed the genetic relationships among species. A 2281-bp RAPD band called PI-Mt-Stb-23 from P. strobus was used as a probe in restriction fragment length polymorphism (RFLP) analysis and produced distinct banding patterns for each species examined, consistent with the highly polymorphic character of DNA-fingerprinting probes.
Base Sequence↗
Suitability of some southern and western pines as hosts for the pine shoot beetle, Tomicus piniperda (Coleoptera: Scolytidae).
The pine shoot beetle, Tomicus piniperda (L.), is an exotic pest that has become established in North America. Discovered in Ohio in 1992, it has since been found in at least 13 states and parts of Canada. The beetle can cause significant growth loss in pines, and it represents a potential threat to trees in areas where it has not yet become established. To evaluate this threat to native pines, field and laboratory tests were conducted on several common and important southern and western species to determine whether they are acceptable hosts for T. piniperda. Comparisons with Pinus sylvestris L., Scots pine, a preferred natural host for the beetle, were made where possible. Measurements of beetle attack success on southern pine billets showed that Pinus taeda L., Pinus echinata Miller, Pinus elliottii var. elliottii Engelmann, Pinus palustris Miller, and Pinus virginiana Miller (loblolly, shortleaf, slash, longleaf, and Virginia pine, respectively) and two western pines, Pinus ponderosa Lawson and Pinus contorta Douglas (ponderosa and lodgepole pine, respectively), were acceptable for breeding material, but brood production was highly variable. Among the southern pines, P. taeda and P. echinata were susceptible to shoot feeding by T. piniperda, whereas P. elliottii was highly resistant and P. palustris seemed to be virtually immune. Shoot feeding tests on the western pines were conducted only in the laboratory, but there was moderate-to-good survival of adults feeding on both species. It seems that if T. piniperda is introduced into the south and west it will likely establish and may cause some damage to native pines. P. taeda may be affected more than other southern pines because it is the most abundant species, it is readily attacked for brood production, which can result in moderately large broods, and the beetle survives well during maturation feeding on P. taeda shoots.
Animals↗
[Characterization of 5S rRNA gene sequence and secondary structure in gymnosperms].
In higher plants the primary and the secondary structures of 5S ribosomal RNA gene are considered highly conservative. Little is known about the 5S rRNA gene structure, organization and variation in gyimnosperms. In this study we analyzed sequence and structure variation of 5S rRNA gene in Pinus through cloning and sequencing multiple copies of 5S rDNA repeats from individual trees of five pines, P. bungeana, P. tabulaeformis, P. yunnanensis, P. massoniana and P. densata. Pinus bungeana is from the subgenus Strobus while the other four are from the subgenus Pinus (diploxylon pines). Our results revealed variations in both primary and secondary structure among copies of 5S rDNA within individual genomes and between species. 5S rRNA gene in Pinus is 120 bp long in most of the 122 clones we sequenced except for one or two deletions in three clones. Among these clones 50 unique sequences were identified and they were shared by different pine species. Our sequences were compared to 13 sequences each representing a different gymnosperm species, and to six sequences representing both angiosperm monocots and dicots. Average sequence similarity was 97.1% among Pinus species and 94.3% between Pinus and other gymnosperms. Between gymnosperms and angiosperms the sequence similarity decreased to 88.1%. Similar to other molecular data, significant sequence divergence was found between the two Pinus subgenera. The 5S gene tree (neighbor-joining tree) grouped the four diploxylon pines together and separated them distinctly from P. bungeana. Comparison of sequence divergence within individuals and between species suggested that concerted evolution has been very weak especially after the divergence of the four diploxylon pines. The phylogenetic information contained in the 5S rRNA gene is limited due to its shorter length and the difficulties in identifying orthologous and paralogous copies of rDNA multigene family further complicate its phylogenetic application. Pinus densata is a diploid hybrid between P. tabulaeformis and P. yunnanensis. Its 5S rDNA composition is consistent with its hybrid origin. 5S rRNA of all gymnosperms published so far could be folded into a general secondary structure. Variation in this secondary structure was detected among species. About 55% of the 120 bp nucleotide positions was variable, in which 68% was on stem regions. Nevertheless, the positions at the end of the stems and those adjacent to loops are conserved. Their stability directly determines the size of the loops. Some mutations such as compensatory base-pair substitutions, and G-U pairing could be regarded as mechanisms for maintaining a stable secondary structure. The loops of the secondary structure are also relatively conserved. It seems that stable helices are necessary for the function of the gene. The conserved nucleotides in the loops are probably involved in the interaction with proteins and/or RNAs or with other nucleotide in the formation of the tertiary structure. However, unlike other reports, Loop E was found quite mutable among pines. These variations together with those on stems might be caused by the presence of pseudogenes among our clones. A preliminary evaluation indicates that only seven of 50 unique sequences are potentially functional genes.
Base Sequence↗
[Resource and ecological distribution of ectomycorrhizal fungi under pine forests of Huangshan Mountain district].
Pinus massoniana and Pinus taiwanensis are the most common and important tree species in the Huangshan Mountain district, and ectomycorrhizae plays an important role in their forestation. Our investigations in 1998-2003 showed that under the pine forests of this district, there were 43 species of ectomycorrhizal fungi belonging to 10 families and 17 genera, of which, 43 were under Pinus massoniana forest, and 12 under Pinus taiwanensis forest. Only a few species were found under young Pinus massoniana forest, with the dominant of Pisolithus tinctorius (Pers.) Coken and Rhizopogon spp., but under mature Pinus massoniana forest, there were plentiful species, with the dominant of Russulaceae, Amanitaceae, Boletaceae and Canthurellaceae. The relationships between woody species and ectomycorrhizal fungi, and between fungi distribution and temperature, moisture and soil condition were discussed in this paper, which would benefit to the further studies on the effects of different ectomyrrhizal fungi to Pinus massoniana and Pinus taiwanensis forests.
China↗
Chromosomal localization of 5S and 18S-5.8S-25S ribosomal DNA sites in five Asian pines using fluorescence in situ hybridization.
Fluorescence in situ hybridization (FISH) was employed on mitotic metaphase chromosome preparations of five Asian Pinus species: Pinus tabuliformis, Pinus yunnanensis, Pinus densata, Pinus massoniana and Pinus merkusii, using simultaneously DNA probes of the 18S rRNA gene and the 5S rRNA gene including the non-transcribed spacer sequences. The number and location of 18S rDNA sites varied markedly (5-10 pairs of strong signals) among the five pines. A maximum of 20 major 18S rDNA sites was observed in the diploid genome (2n = 24) of P. massoniana. The 5S rDNA FISH pattern was less variable, with one major site and one minor site commonly observed in each species. The differentiation of rDNA sites on chromosomes among the five pines correlates well with their phylogenic positions in Pinus as reconstructed from other molecular data. P. densata, a species of hybrid origin, resembles its parents ( P. tabuliformis and P. yunnanensis), including some components characteristic of each parent in its pattern. However, the species is unique, showing new features resulting possibly from recombination and genome reorganization.
Asia↗
[Analysis of pine pollen by using FTIR, SEM and energy-dispersive X-ray analysis].
Infrared spectroscopy (IR), scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDX) were used to analyze nutrients in four pine pollen powder samples. The IR fingerprints showed that each of the samples, pinus massoniana, pinus yunnanensis, pinus tabulaeformis, and pinus densiflora, respectively had its own characteristic infrared spectrum. Based on the difference of the relative intensity of those characteristic absorption peaks, the IR fingerprints can be used for the identification of the four kinds of pine pollen samples. The broken pollen of pinus was more easily to release nutritional components for the distinct difference IR fingerprints of natural and broken masson pine pollen samples. As a result of SEM, four kinds of pollen grains were oblong or subspheroidal in distal face and proximal face. The exine sculpture of the four kinds of samples were granulous and almost the same, but there was some difference of the size of pollen grains. The main morphologic change of the broken pollen was that the air bags were separated from pollen particles, and part of the main body of pollen particles was broken. The energy-dispersive X-ray analysis results showed that eleven elements, including Mg, Se, Si, Sr, P, S, Cl, K, Ca, Mn, and Fe, existed and the highest content in pollen of pinus was K element. The contents of trace elements were different in different kinds of pollen of pinus. The element intensity in broken masson pine pollen was distinctlyhigher than that innatural masson pine pollen.
Microscopy, Electron, Scanning↗
Ammonium and nitrate acquisition by plants in response to elevated CO2 concentration: the roles of root physiology and architecture.
We examined changes in root system architecture and physiology and whole-plant patterns of nitrate reductase (NR) activity in response to atmospheric CO2 enrichment and N source to determine how changes in the form of N supplied to plants interact with rising CO2 concentration ([CO2]). Seedlings of Betula alleghaniensis Britt. and Pinus strobus L., which differ in growth rate, root architecture, and the partitioning of NR activity between leaves (Betula) and roots (Pinus), were grown in ambient (400 microl l(-1)) and elevated (800 microl l(-1)) [CO2] and supplied with either nitrate (NO3-) or ammonium (NH4+) as their sole N source. After 15 weeks of growth, plants were harvested and root system architecture, N uptake kinetics, and NR activity measured. Betula alleghaniensis responded to elevated [CO2] with significant increases in growth, regardless of the source of N. Pinus strobus showed no significant response in biomass production or allocation to elevated [CO2]. Both species exhibited significantly greater growth with NH4+ than with NO3-, along with lower root:shoot biomass ratios. Betula showed significant increases in total root length in response to elevated [CO2]. However, root N uptake rates in Betula (for both NO3- and NH4+) were either reduced or unchanged by elevated [CO2]. Pinus showed the opposite response to elevated [CO2], with no change in root architecture, but an increase in maximal uptake rates in response to elevated [CO2]. Nitrate reductase activity (on a mass basis) was reduced in leaves of Betula in elevated [CO2], but did not change in other tissues. Nitrate reductase activity was unaffected by elevated [CO2] in Pinus. Scaling this response to the whole-plant, NR activity was reduced in elevated [CO2] in Betula but not in Pinus. However, because Betula plants were larger in elevated [CO2], total whole-plant NR activity was unaffected.
Betula↗
Quantifying carbon budgets of conifer Mediterranean forest ecosystems, Turkey.
Aboveground biomass, aboveground litterfall, and leaf litter decomposition of five indigenous tree stands (pure stands of Pinus brutia, Pinus nigra, Cedrus libani, Juniperus excelsa, and a mixed stand of Abies cilicica, P. nigra, and C. libani) were measured in an eastern Mediterranean evergreen needleleaf forest of Turkey. Measurements were converted to regional scale estimates of carbon (C) stocks and fluxes of forest ecosystems, based on general non-site-specific allometric relationships. Mean C stock of the conifer forests was estimated as 97.8 +/- 79 Mg C ha(-1) consisting of 83.0 +/- 67 Mg C ha(-1) in the aboveground and 14.8 +/- 12 Mg C ha(-1) in the belowground biomass. The forest stands had mean soil organic carbon (SOC) and nitrogen (SON) stocks of 172.0 +/- 25.7 Mg C ha(-1) and 9.2 +/- 1.2 Mg N ha(-1), respectively. Mean total monthly litterfall was 376.2 +/- 191.3 kg C ha(-1), ranging from 641 +/- 385 kg C ha(-1) for Pinus brutia to 286 +/- 82 kg C ha(-1) for Cedrus libani. Decomposition rate constants (k) for pine needles were 0.0016 for Cedrus libani, 0.0009 for Pinus nigra, 0.0006 for the mixed stand, and 0.0005 day(-1) for Pinus brutia and Juniperus excelsa. Estimation of components of the C budgets revealed that the forest ecosystems were net C sinks, with a mean sequestration rate of 2.0 +/- 1.1 Mg C ha(-1) yr(-1) ranging from 3.2 +/- 2 Mg C ha(-1) for Pinus brutia to 1.6 +/- 0.6 Mg C ha(-1) for Cedrus libani. Mean net ecosystem productivity (NEP) resulted in sequestration of 98.4 +/- 54.1 Gg CO2 yr(-1) from the atmosphere when extrapolated for the entire study area of 134.2 km2 (Gg = 10(9) g). The quantitative C data from the study revealed the significance of the conifer Mediterranean forests as C sinks.
Biomass↗
Rapid expansion of microsatellite sequences in pines.
Microsatellite persistence time and evolutionary change was studied among five species of pines, which included a pair of closely related species (Pinus sylvestris and Pinus resinosa) in the subgenus Pinus, their relative Pinus radiata, and another closely related species pair (Pinus strobus and Pinus lambertiana) in the subgenus Strobus. The effective population sizes of these species are known to have ranged from the very small bottlenecks of P. resinosa to vast populations of P. sylvestris. This background allowed us to place the microsatellite evolution in a well-defined phylogenetic setting. Of 30 loci originating from P. strobus and P. radiata, we were able to consistently amplify 4 in most of the these pine species. These priming sites had been conserved for over 100 Myr. The four microsatellites were sequenced in the five species. Flanking sequences were compared to establish that the loci were orthologous. All microsatellites had persisted in these species, despite very different population sizes. We found a recent microsatellite duplication: a closely related pair of loci in P. strobus, where the other four species had just one locus. On two independent occasions, the repeat area of this same microsatellite (locus RPS 105a/b) had grown from a very low repeat number to 15 or 17 in the last 10-25 Myr. Other parts of the same compound microsatellite had remained virtually unchanged. Locus PR 4.6 is known to be polymorphic in both P. radiata and P. sylvestris, but the polymorphism in the two species is due to different motifs. The very large pine genomes are highly repetitive, and microsatellite loci also occur as gene families.
Base Sequence↗
[Effect of elevated CO2 concentration on carbohydrate and nitrogen contents in seedlings foliage of three tree species in Changbai mountain].
The contents of sucrose, fructose, soluble total sugar, starch and total nitrogen were analyzed in seedlings of Pinus koraiensis, Pinus sylvestriformis and Fraxinus mandshurica grown for three growing seasons in open-top chambers in Changbai mountain under elevated CO2 (700, 500 mumol.mol-1) and ambient CO2 (350 mumol.mol-1) concentrations. The results showed that in the first two growing seasons the treatment of 700 mumol.mol-1 CO2 accumulated the contents of starch in Pinus sylvestriformis and Fraxinus mandshurica seedlings, while total nitrogen content significantly decreased in Pinus koraiensis seedlings under 700 and 500 mumol.mol-1 CO2. The content of starch increased and the content of total nitrogen decreased in Pinus koraiensis and Fraxinus mandshurica seedlings grown under 700, 500 mumol.mol-1 CO2 at the first two weeks in the third growing season. The change of starch and total nitrogen in Fraxinus mandshurica at the eighth week was similar to the first and second week. There was no significant increase or decrease of C and N content in Pinus sylvestriformis at the third growing season. CO2 concentration affected the forms of carbohydrate accumulation in foliage.
Carbohydrates↗
[Water storage characteristics of ground covers under three forests in Three Gorges area].
Through water holding experiments and the survey of ground covers under three forests (mixed forest of Quercus variabilis and Pinus massoniana, pure Quercus variabilis forest and pure Pinus massoniana forest) in Three Gorges Area, the hydrological characteristic parameters, e.g., maximum water holding capacity and water absorption speed, were measured. The results showed that the maximum water holding capacity of moss under pure Quercus variabilis forest is the highest (303.1% of its dry weight), that under mixed forest of Quercus variabilis and Pinus massoniana was 283.8%, and that under pure Pinus massoniana forest was 242.3%. The maximum water holding capacity of litter under mixed forest stand of Quercus variabils and Pinus massoniana was 282.2% of its dry weight, that under pure Quercus variabilis forest is 262.5%, that under pure Pinus massoniana forest was 239.3%. The equation between water absorption speed of ground cover and its immersed period could be S = kt(n). The results also showed that when the forests were all in mid-age, the water holding ability of the mosses was higher than that of the litters under the same forest. The ground cover's variation with its immersed period had no relation to forest types.
Absorption↗
The effect of different pine hosts on the sampling of Rhizopogon spore banks in five Eastern Sierra Nevada forests.
Our primary goal was to determine whether detection of Rhizopogon internal transcribed spacer (ITS) groups is affected by the pine species used in seedling bioassays. Our secondary goal was to investigate composition of Rhizopogon spore banks in the Eastern Sierra Nevada of California, a previously unsampled region. We used seedlings of Pinus contorta, Pinus jeffreyi, Pinus lambertiana, and Pinus muricata as bioassay plants and identified the Rhizopogon retrieved by internal transcribed spacer (ITS) sequence analysis. We found that each of the pine species retrieved all of the abundant Rhizopogon ITS groups, but there were significant differences among pines in the richness of Rhizopogon ITS groups recovered. Pinus muricata recovered all ITS groups found in this study and was significantly better than P. lambertiana. Rhizopogon communities from the five sampled sites contained six to eight ITS groups per site, with two unique sequence groups and a higher abundance of the Rhizopogon ellenae and Rhizopogon arctostaphyli groups than at previously sampled sites. These results show high cross-receptivity between Rhizopogon and pine species, and regional patterns in spore bank composition.
Basidiomycota↗
[Biomass and carbon storage of ground bryophytes under six types of young coniferous forest plantations].
This paper studied the biomass and carbon storage of the ground bryophytes under young Picea balfouriana (P), Pinus tabulaeformis (Y), Pinus armandii (H), Larix kaempferi (L), Picea balfouriana-Pinus tabulaeformis (P-Y), and Pinus tabulaeformis-Pinus armandii (Y-H) forest plantations in the upper reach of Minjiang River, Sichuan Province. The results showed that total biomass and carbon storage of ground bryophytes were relatively low, being 3.11 - 460.36 kg x hm(-2) and 1.12 +/- 0.03 x 168.95 +/- 0.92 kg x hm(-2), respectively. On plot level, only the bryophyte biomass between forest P and others, and the carbon storage between forest L and others were significantly different. The ground bryophyte had the highest biomass and carbon storage under forest P, while the lowest ones under forest H. Comprehensive analysis suggested that forest type and its structural feature might be the important factors determining the biomass and carbon storage of ground bryophytes, and thinning was an important measure to improve ground bryophyte growth and biomass production.
Biomass↗
Paternal chloroplast inheritance patterns in pine hybrids detected with trnL-trnF intergenic region polymorphism.
The inheritance patterns of the chloroplast genomes of shortleaf pine ( Pinus echinata Mill.), loblolly pine ( Pinus taeda L.) and slash pine ( Pinus elliottii Engelm.) were investigated through the trnL-trnF intergenic spacer polymorphism analysis. The DNA sequences of this spacer differ among these three closely related Pinus species. A modified 'cold' PCR-SSCP (single-strand conformation polymorphism) analysis of this spacer shows that the artificial hybrids (F1) from the shortleaf pine (seed parent) x loblolly pine (pollen parent) cross, exhibit the loblolly pine profile. Additionally, nine putative hybrids between shortleaf pine and loblolly pine, previously identified by the IDH (Isocitrate dehydrogenase) allozyme marker, presented the shortleaf pine profile indicating that shortleaf pine, not loblolly pine, sired all of the putative hybrids. Nondenatured polyacrylamide-gel electrophoresis of the trnL-trnF intergenic spacer demonstrated that the artificial hybrids (F1) from the cross, slash pine (seed parent) x shortleaf pine (pollen parent), present the shortleaf pine profile. Those results confirmed that the chloroplast genome is paternally inherited in these three species of the genus Pinus. The significance of the trnL-trnF intergenic region polymorphism and our modified 'cold' SSCP protocol for population genetic studies is discussed.
Journal Article↗
Abietoid seed fatty acid compositions--a review of the genera Abies, Cedrus, Hesperopeuce, Keteleeria, Pseudolarix, and Tsuga and preliminary inferences on the taxonomy of Pinaceae.
The seed fatty acid (FA) compositions of Abietoids (Abies, Cedrus, Hesperopeuce, Keteleeria, Pseudolarix, and Tsuga) are reviewed in the present study in conclusion to our survey of Pinaceae seed FA compositions. Many unpublished data are given. Abietoids and Pinoids (Pinus, Larix, Picea, and Pseudotsuga)-constituting the family Pinaceae-are united by the presence of several delta5-olefinic acids, taxoleic (5,9-18:2), pinolenic (5,9,12-18:3), coniferonic (5,9,12,15-1 8:4), keteleeronic (5,11-20:2), and sciadonic (5,11,14-20:3) acids, and of 14-methyl hexadecanoic (anteiso-17:0) acid. These acids seldom occur in angiosperm seeds. The proportions of individual delta5-olefinic acids, however, differ between Pinoids and Abietoids. In the first group, pinolenic acid is much greater than taxoleic acid, whereas in the second group, pinolenic acid is greater than or equal to taxoleic acid. Moreover, taxoleic acid in Abietoids is much greater than taxoleic acid in Pinoids, an apparent limit between the two subfamilies being about 4.5% of that acid relative to total FA. Tsuga spp. appear to be a major exception, as their seed FA compositions are much like those of species from the Pinoid group. In this respect, Hesperopeuce mertensiana, also known as Tsuga mertensiana, has little in common with Abietoids and fits the general FA pattern of Pinoids well. Tsuga spp. and H. mertensiana, from their seed FA compositions, should perhaps be separated from the Abietoid group and their taxonomic position revised. It is suggested that a "Tsugoid" subfamily be created, with seed FA in compliance with the Pinoid pattern and other botanical and immunological criteria of the Abietoid type. All Pinaceae genera, with the exception of Pinus, are quite homogeneous when considering their overall seed FA compositions, including delta5-olefinic acids. In all cases but one (Pinus), variations from one species to another inside a given genus are of small amplitude. Pinus spp., on the other hand, have highly variable levels of delta5-olefinic acids in their FA compositions, particularly when sections (e.g., Cembroides vs. Pinus sections) or subsections (e.g., Flexiles and Cembrae subsections from the section Strobus) are compared, although they show qualitatively the same FA patterns characteristic of Pinoids. Multicomponent analysis of Abietoid seed FA allowed grouping of individual species into genera that coincide with the same genera otherwise characterized by more classical botanical criteria. Our studies exemplify how seed FA compositions, particularly owing to the presence of delta5-olefinic acids, may be useful in sustaining and adding some precision to existing taxonomy of the major family of gymnosperms, Pinaceae.
Abies↗
Modern pollen and stomate deposition in lake surface sediments from across the treeline on the Kola Peninsula, Russia.
We sampled and analyzed surface sediments from 31 lakes along a latitudinal transect crossing the coniferous treeline on the Kola Peninsula, Russia. The major vegetation zones along the transect were tundra, birch-forest tundra, pine-forest tundra, and forest. The results indicate that the major vegetation types in our study area have distinct pollen spectra. Sum-of-squares cluster analysis and principal components analysis (PCA) groupings of pollen sites correspond to the major vegetation zones. PCA ordination of taxa indicates that the first axis separates taxa typical of the forest zone (Pinus, Picea) from taxa typical of tundra and forest-tundra zones (Polypodiaceae, Ericaceae, and Betula). The current position of the coniferous treeline, defined in our region by Pinus sylvestris, occurs roughly where Pinus pollen values reach 35% or greater. Arboreal pollen (AP)/non-arboreal pollen (NAP) ratios were calculated for each site and plotted against geographic distance along the transect. AP/NAP ratios of 7 or greater are found within pine-forest tundra and forest vegetation zones. Pinus stomates (dispersed stomatal guard cells) are absent from sites north of the coniferous treeline and all but two samples from the forested sites contain stomates. Stomate concentrations among the samples are highly variable and range from 10 to 458 per ml and positively correlate with the changing Pinus pollen values.
Journal Article↗