Dry-matter Production and Photosynthesis in Pine Seedlings

Growth analysis and photosynthesis measurements were carriedout on first-year seedlings of Pinus radiata, P. contorta, andP. nigra. P. sylvestris was also included in two growth-analysisexperiments. There appeared to be no difference in relativegrowth-rate (RGR) between the species mentioned, except betweenP. radiata and P. nigra. It was found that when the level ofmineral nutrition was high, P. radiata had a higher RGR thanP. nigra and that the reverse was true at low mineral nutrientlevels. There was no difference in net assimilation rate (NAR)between the species, but NAR appeared to increase and decreasewith mineral nutrient supply. Net photosynthesis per unit of leaf was somewhat higher in P.radiata than in P. contorta; P. nigra had a lower photosyntheticrate than either P. radiata or P. contorta.     

Nutrient Supply, Dry-matter Production and Nutrient Uptake of Forest Tree Seedlings

The dry-matter production and nutrient uptake of forest-treeseedlings grown under controlled levels of nutrition in sub-irrigatedsand culture were investigated. Hardwood seedlings attainedgreater dry weight than conifer seedlings, and Pinus radiataa greater dry weight than P. contorta and P. nigra, but thesegreater dry weights were not related to greater leaf/weightratios, although seed size may have been an important influenceon final seedling dry weight. P. radiata was found to have alower requirement for P than P. contorta and P. nigra in oneexperiment. The demand (total nutrient uptake per unit of time) made bythree species for nutrients upon a site was shown to dependmore upon growth-rate per annum than on efficiency (quantityof nutrients required to produce a unit of dry matter). It isconcluded that the ability of tree species to grow satisfactorilyon soils of low nutrient status depends largely on their abilityfor relatively slow growth. On the other hand, species showinggood response to favourable sites may also make satisfactorygrowth on poor sites.     

Pollen Tube Development and Characteristics of the Protein Emission in Conifers

When ripe, viable pollen of Pinus contorta, Pinus nigra, Piceasitchensis, Abies alba and Cedrus deodara is germinated on asuitable artificial substrate, the process of pollen tube growthbegins 12–36 h later, according to the species. The tubeemerges at the leptoma, a structurally specialized site in thepollen wall, and the early tube wall is continuous with thetwo microfibrillar intine strata within the grain. Later inpollen tube development, when cytoplasmic zonation has beenestablished, only the inner of these two wall layers is differentiated. Cytochemical methods show that, during hydration and throughoutthe period of tube growth in culture, proteins are releasedfrom the pollen grains; before germination most conspicuouslyfrom the leptoma, subsequently from the tube itself. The emissioncontains a number of hydrolytic enzymes and a non-catalyticmoiety. Gel-electrofocusing reveals that the hydrolases releasedfrom germinating Pinus contorta pollen include several acidphosphatase and esterase isozymes, and that there are differencesbetween the composition of the emission and the spectrum ofsoluble proteins extracted from the pollen grains before germination.Analysis by immunodiffusion demonstrates that two componentswith antigenic characteristics present in the quiescent pollengrains are represented in the emission. The possible utilityof the released components in the biology of conifer reproductionis discussed. Pinus contorta, Pinus nigra, Picea sitchensis, Abies alba, Cedrus deodara, lodgepole pine, Austrian pine, Sitka spruce, European silver fir, deodar, pollen tube, pollen germination, protein release, isoelectric focusing     

The 5S RNA genes inPinus radiata and the spacer region as a probe for relationships betweenPinus species

The 5S RNA genes inPinus radiata occur in two size classes of about 850 and 525 bp in length. Representatives from both the long and short size classes were cloned and sequenced. The primary difference in the two size classes was shown to be a 330 bp insertion in the spacer region of the long units. Within an individual breeding clone ofP. radiata there was some sequence heterogeneity between representatives of the short class. The 5S RNA genes in thirty pine species were characterised using either a clone of the short size class or a subclone of the 330 bp insertion characterizing the long size class. Eleven species of subg.Strobus were examined and all lacked the long type of unit of radiata pine. The New World species of subg.Pinus all had both short and long units whereas the Old World species had long units. The implications of these results for the evolution of the 5S DNA sequences and the phylogenetic relationships withinPinus are discussed.     

Mapped DNA probes from loblolly pine can be used for restriction fragment length polymorphism mapping in other conifers

A high-density genetic map based on restriction fragment length polymorphisms (RFLPs) is being constructed for loblolly pine (Pinus taeda L.). Consequently, a large number of DNA probes from loblolly pine are potentially available for use in other species. We have used some of these DNA probes to detect RFLPs in 12 conifers and an angiosperm. Thirty complementary DNA and two genomic DNA probes from loblolly pine were hybridized to Southern blots containing DNA from five species of Pinus (P. elliottii, P. lambertiana, P. radiata, P. sylvestris, and P. taeda), one species from each of four other genera of Pinaceae (Abies concolor, Larix laricina, Picea abies, and Pseudotsuga menziesii), one species from each of three other families of Coniferales [Sequoia sempervirens (Taxodiaceae), Torreya californica (Taxaceae) and Calocedrus decurrens (Cupressaceae)], and to one angiosperm species (Populus nigra). Results showed that mapped DNA probes from lobolly pine will cross-hybridize to genomic DNA of other species of Pinus and some other genera of the Pinaceae. Only a small proportion of the probes hybridized to genomic DNA from three other families of the Coniferales and the one angiosperm examined. This study demonstrates that mapped DNA probes from loblolly pine can be used to construct RFLP maps for related species, thus enabling the opportunity for comparative genome mapping in conifers.     

Assimilation Rate and Growth of Lolium Populations in the Glasshouse in Contrasting Light Intensities

Using growth-analysis techniques, the variation in relativegrowth-rate (RGR) and its components, net assimilation rate(NAR), and leaf-area ratio (LAR), was examined in 18 populationsof L. perenne, six of L. multiflorum, and two hybrid cultivarsfrom contrasting climatic and agronomic origins, grown at lowand high light intensities in the glasshouse. Significant differences between populations were found for RGR,NAR, and LAR at both light intensities. At both intensitiesthe annual or biennial multiflorum group had a greater LAR anda lower specific leaf weight and chlorophyll content than theperennial perenne group. At the low intensity this was compensatedby a greater NAR in the perenne group, with no resultant differencein RGR. At the high intensity there was no difference betweenthe groups in NAR, and hence a greater RGR in the multiflorumgroup. Within the perenne and multiflorum groups, at both light intensities,the variation between populations in RGR was based on differencesin NAR rather than in LAR. There was no regular correlationof NAR with either specific leaf weight, or chlorophyll contentat either light intensity, though at low light intensity itwas significantly correlated with shoot-root ratio.     

Structure, Production and Leaf Area Dynamics: A Comparison of Lodgepole Pine and Sunflower

Populations of lodgepole pine (Pinus contorta var latifoliaEngelm) and sunflower (Heltanthus annuus L) were examined tocompare the influence of stand density on canopy structure andthe association between canopy structure and the productionof stem volume The plastic responses of canopy structure tocompetitive interactions indicated that the structural dynamicsof lodgepole pine and sunflower populations were similar, thoughthe degree of plastic response differed The influence of canopystructure on the production of stem volume, however, was fundamentallydifferent efficiency decreased as the mean crown size of lodgepolepine populations increased, but this decrease did not occurin sunflower populations This difference was attributed to thelarge accumulation of branch biomass required to display foliageeffectively in the canopies of the perennial lodgepole pine,accumulation which does not occur in the annual sunflower Lodgepole pine, Pinus contorta var latifolia Engelm, sunflower, Helianthus annuus L, leaf area, canopy structure, stand production, carbon allocation     

Difference in cuticular transpiration and sclerophylly in juvenile and adult pine needles relates to the species-specific rates of development

Pinus species show remarkable ontogenetic differences in needle morphology (heterophylly) between juvenile and adult vegetative phases. This developmental shift may play an adaptative role in their success under diverse habitats. As a first step to know the functional differences between each vegetative phase, we compared water loss through the cuticles of juvenile and adult needles of 21-month-old nursery-grown seedlings of nine hard pine species. Cuticular transpiration (CT), calculated after complete stomatal closure, was obtained by leaf-drying curves, and was related to leaf, ontogenetic and climatic parameters. The rate of cuticular transpiration (RCT) between juvenile and adult needles differed across pine species, and in particular segregated the Mediterranean species Pinus canariensis and P. halepensis, from the Eurasian P. uncinata and introduced species P. radiata. For these species, RCT was always higher in juvenile needles. The different leaf and ontogenic parameters studied were correlated with the variation in RCT among the nine pine species. We discuss this relationship in the light of the species ecology. Besides their possible adaptive interpretation, these results suggest an underlying need to consider the ontogenetic heterophylly when assessing functional traits in hard pine seedlings, in particular those traits that govern water relations.     

Paternal leakage of mitochondrial DNA inPinus

Summary We studied mitochondrial DNA restriction fragment length polymorphism in 11 parents and 125 seedlings of 23 controlled matings within and between jack pine (Pinus banksiana Lamb.) and lodgepole pine (P. contorta Dougl.). A potential mitochondrial distinction between these two conifers was evident in the parental samples. Only maternal mitochondrial restriction fragments were observed in a majority of the seedlings, which is consistent with results from angiosperms and other members of the genusPinus L. However, we detected exclusively paternal mitochondrial DNA in six of the seedlings. These unusual seedlings were not attributable to heteroplasmy or contamination of the experimental material, indicating that mitochondrial inheritance was not strictly maternal. Paternal mitochondrial leakage inPinus may permit novel insights into the transmission genetics and evolution of organellar polymorphisms.     

A comparative cytogenetic analysis of five pine species from North America, Pinus banksiana, P. contorta, P. monticola, P. resinosa, and P. strobus

The genus Pinus comprises more than 100 species, which are widely distributed in the Northern hemisphere. Cytogenetic information on North American pines is very limited despite their economic importance. In the present study, a detailed comparative cytogenetic analysis is presented for five pine species from North America, P. resinosa, P. monticola, P. contorta, P. banksiana, and P. strobus. Morphometric analysis and physical mapping of rDNA probes were performed. The karyotype of P. monticola was considered ancestral with small difference in relative chromosome lengths. P. banksiana, P. contorta, and P. strobus karyotypes were considered semi-asymmetrical and less ancestral type. P. banksiana showed five secondary constrictions, P. strobus six, and P. contorta eight. P. resinosa karyotype was semi-asymmetrical and derived with 14 secondary constrictions identified on eight different chromosomes. Karyological data were consistent with molecular cytogenetic information. A significant association was observed between the number and locations of secondary constrictions and the 18S-5.8S-26S rDNA sites detected using fluorescence in situ hybridization. The two methods were used to establish a reliable comparative karyotype of the selected pines. In general, karyotype and chromosome evolution were not related to genetic relationships among pine species studied.     

<Emphasis Type="Italic">Pinus contorta</Emphasis> invasion into treeless steppe reduces species richness and alters species traits of the local community

Pinus contorta, one of the most invasive tree species in the world, has been proposed as a model species for improving our understanding of invasion ecology. In this study, we assessed the impact of P. contorta invasions on the species richness, diversity and species traits of a resident treeless steppe community. In a Pinus contorta invasion gradient (Patagonia, Chile), we surveyed vegetation from high canopy closure pine invasion to treeless steppe, and computed species richness, diversity and Sørensen similarity indexes. For all species, we determined functional trait values from the literature, data bases, and personal observations. Species richness and diversity were related to canopy cover (a proxy for invasion intensity) using generalized linear mixed-effects models. Changes in species traits due to canopy cover were analyzed using RLQ ordination analysis and the fourth-corner analysis. We found that Pinus contorta canopy cover significantly reduced the number of native species by 70 %, implying a strong effect on species exclusion. A few native species, however, prevail in the novel conditions (e.g. Baccharis magellanica, Acaena integerrima). Species traits changed significantly with increasing pine canopy cover, where P. contorta promoted the existence of traits related to shade-tolerance and conservative reproductive strategies. We conclude that the negative impacts of Pinus contorta into the treeless steppe, including a reduction in the number of species and the shifting to traits adapted to tolerate shade and associated with conservative reproductive strategies, can have severe implications for the conservation of biodiversity and ecosystem functioning where it invades.     

Tree response and mountain pine beetle attack preference,reproduction and emergence timing in mixed whitebark and lodgepole pine stands

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Host selection behaviour of the banded pine weevil,Pissodes castaneus (Coleoptera: Curculionidae)

1. Pissodes castaneus represents an emerging pest species for Pinus spp. production in Latin America. This species attacks all the cultivated pine species in Patagonia Argentina causing wood damage and tree death. The objectives of this work were to describe the host preference behaviour of P. castaneus and the influence of wood damage by conspecifics on its host selection.
2. In two-choice bioassays, P. castaneus showed a feeding preference for Pinus contorta over P. ponderosa. However, percent weight gain when feeding on either species was similar.
3. In other bioassays, P. castaneus spent more time in areas with twigs on which other conspecifics had recently fed, although they were able to successfully feed on twigs without previous damage.
4. These results show that while P. castaneus can successfully colonize different pine species, P. contorta may be more susceptible to attack than P. ponderosa. Silvicultural management should be prioritized considering the weevil's preference for attacking damaged hosts.

     

Differentiating manool and 13-epimanool with NMR chiral shift reagents

Use of NMR chiral shift reagents showed that a compound isolated from Pinus contorta bark and Tsuga heterophylla wood was 13-epimanool. Southern pine (Pinus spp.) tall oil contained a mixture of manool and 13-epimanool.     

The co-occurrence of ectomycorrhizal,arbuscular mycorrhizal,and dark septate fungi in seedlings of four members of the Pinaceae

Although roots of species in the Pinaceae are usually colonized by ectomycorrhizal (EM) fungi, there are increasing reports of the presence of arbuscular mycorrhizal (AM) and dark septate endophytic (DSE) fungi in these species. The objective of this study was to determine the colonization patterns in seedlings of three Pinus (pine) species (Pinus banksiana, Pinus strobus, Pinus contorta) and Picea glauca x Picea engelmannii (hybrid spruce) grown in soil collected from a disturbed forest site. Seedlings of all three pine species and hybrid spruce became colonized by EM, AM, and DSE fungi. The dominant EM morphotype belonged to the E-strain category; limited colonization by a Tuber sp. was found on roots of Pinus strobus and an unknown morphotype (cf. Suillus–Rhizopogon group) with thick, cottony white mycelium was present on short roots of all species. The three fungal categories tended to occupy different niches in a single root system. No correlation was found between the percent root colonized by EM and percent colonization by either AM or DSE, although there was a positive correlation between percent root length colonized by AM and DSE. Hyphae and vesicles were the only AM intracellular structures found in roots of all species; arbuscules were not observed in any roots.     

Role of insect vectors in epidemiology and invasion risk of <Emphasis Type="Italic">Fusarium circinatum</Emphasis>, and risk assessment of biological control of invasive <Emphasis Type="Italic">Pinus contorta</Emphasis>

Pitch canker, caused by the pathogen Fusarium circinatum, is a serious disease of pines, Pinus species. It is a threat to natural and planted pine forests, and to date it has invaded countries across five continents. Pine-feeding insects can play a key role in the epidemiology of the disease, as wounding agents allowing pathogen access or as vectors transmitting the pathogen from infected to healthy trees. We reviewed the role of insects in the epidemiology of pitch canker worldwide and assessed which insects are present in New Zealand that may act as wounding agents or vectors to determine whether pathogen invasion could adversely affect Pinus radiata plantation forests and urban trees. We also evaluated whether cone or seed insects of pines could be introduced as biological control agents of invasive Pinus contorta and how this may affect the impact of a potential F. circinatum invasion. As there are no native pines or other Pinaceae in New Zealand, there are only a few pine insects, mainly accidental introductions. None of the insects recorded on pines in New Zealand is likely to be a vector, suggesting low disease risk. Of six potentially suitable biocontrol candidates, the European pine cone weevil Pissodes validirostris is the most promising regarding host specificity and impact on seed production, but there is uncertainty about its ability to act as a vector of F. circinatum. Our methodology to review and evaluate the vector potential of pine associates can be used as a generic framework to assess the potential impacts of F. circinatum invasion.     

Ontogenetic differentiation between Mediterranean and Eurasian pines (sect. Pinus) at the seedling stage

Heteroblastic development in pine seedlings includes extreme morphological changes with still unclear adaptive and evolutionary significance. In particular, Mediterranean and Eurasian pines (section Pinus) living in the Mediterranean basin seem to follow quite distinct developmental trajectories at the seedling stage. Aiming to confirm this ontogenetic differentiation we performed a nursery experiment with seedlings of five Mediterranean pines (Pinus pinaster, P. brutia, P. halepensis, P. pinea and P. canariensis) and three Eurasian pines (P. sylvestris, P. uncinata, and P. nigra subsp. salzmannii), also including P. radiata as an outgroup. After destructive analyses at two harvest times (9 and 32 weeks), we found sharp differentiation between Mediterranean and Eurasian pines in a combination of traits linked to shoot heteroblasty. In particular, Mediterranean pines showed a marked delay in the proportion of adult needles to total needles in the shoot compared to Eurasian species, especially at the second harvest. However, two Mediterranean pines, P. pinaster and P. brutia showed a slightly higher proportion of secondary needles, and a higher rate of budset at a more advanced stage (68 weeks) compared to the other three Mediterranean species. Meaningfully, the outgroup P. radiata was the only species combining a high proportion of adult foliage since the first harvest with a delayed formation of the first terminal bud. We discussed the adaptive significance of these findings at the light of species’ climatic niches and life histories.     

An Examination of the Differences in Dry Matter Production shown by Some Progenies of Pinus sylvestris L.

A study was carried out to determine the extent of the variationin growth rate between several selected progenies of Scots pine{Pinus sylvestris L.) and the physiological characteristicsunderlying such variation, using growth analysis and directmeasurement of photosynthetic rates. Differences in relativegrowth rate (RGR) could be demonstrated for first and secondyear seedling progenies, and these largely reflected differencesin net assimilation rate (NAR). The relative performance ofthe progenies in different experiments was not always the same,although the highest RGR was shown by the same progeny in bothfirst-year and second-year seedlings. For most progenies theobservations were extended to 14-year-old trees growing in fieldtrials established by the Forestry Commission. Comparisons ofthe relative height growth rates (RHGR) of these trees showedno significant differences between the progenies, apparentlybecause the growth rates were limited by the site conditions.Thus, the size differences at the end of the fourteenth yearprobably still reflected differences in RGR which occurred duringthe seedling stages in the nursery. The significance of theseobservations for the assessment of performance in tree breedingprogrammes is discussed.     

Antibacterial effects of knotwood extractives on paper mill bacteria

Hydrophilic knotwood extracts from 18 wood species were assessed in disc diffusion and liquid culture tests for antibacterial effects against three species of paper mill bacteria. The Pinus sylvestris, P. resinosa, P. contorta, and P. banksiana extracts decreased or inhibited bacterial growth. The susceptibility order was P. sylvestris > P. resinosa > P. contorta > P. banksiana, correlating with the concentrations of pinosylvin and pinosylvin monomethyl ether in these wood species. Also, Pseudotsuga menziesii and Thuja occidentalis extracts had a small inhibitory effect. The Gram-positive Bacillus coagulans was more susceptible to the extracts than the Gram-negative Burkholderia multivorans and Alcaligenes xylosoxydans. The main components in the Pinus knotwood extracts were pinosylvin monomethyl ether and pinosylvin, suggesting these to be the active components. Therefore, pure pinosylvin, pinosylvin monomethyl ether, and dihydro-pinosylvin monomethyl ether were also tested. All compounds showed antibacterial effects. However, higher concentrations were needed for these pure compounds than for the knotwood extracts. Pinosylvin had stronger antibacterial effects than pinosylvin monomethyl ether. This work shows that knotwood extracts, especially from Pinus species, have a potential for use as natural biocides in papermaking.     

Biochemical differences between embryogenic and nonembryogenic calli of conifers

Summary Embryogenic and nonembryogenic calli of loblolly pine (Pinus taeda), Eastern white pine (P. strobus), pond pine (P. serotina), white spruce (Picea glauca), and European larch (Larix decidua) were analyzed for biochemical parameters previously shown to be indicative of an embryogenic state in Norway spruce (Picea abies). Concentrations of glutathione and total reductants as well as rates of ethylene evolution and incorporation of radioactive leucine into protein in the two callus types were consistent with the Norway spruce observations. Embryogenic potential of loblolly pine and pond pine callus was predicted by biochemical analysis in advance of the appearance of somatic embryos. Other parameters such as isozyme patterns and SDS-PAGE of soluble proteins could also be used to distinguish embryogenic from nonembryogenic conifer callus. Among the species investigated, white spruce was the most difficult to sort by these methods.