Julianne O'Reilly-Wapstra

Developing near infrared spectroscopy models for predicting chemistry and responses to stress in Pinus radiata (D. Don)

Publisher: SAGE Publications

Date: 28-04-2021

DOI: 10.1177/09670335211006526

Abstract: Incorporating chemical traits in breeding requires the estimation of quantitative genetic parameters, especially the levels of additive genetic variation. This requires large numbers of s les from pedigreed populations. Conventional wet chemistry procedures for chemotyping are slow, expensive and not a practical option. This study focuses on the chemical variation in Pinus radiata, where the near infrared (NIR) spectral properties of the needles, bark and roots before and after exposure to methyl jasmonate (MJ) and artificial bark stripping (strip) treatments were investigated as an alternative approach. The aim was to test the capability of NIR spectroscopy to (i) discriminate s les exposed to MJ and strip assessed 7, 14, 21 and 28 days after treatment from untreated s les, and (ii) quantitatively predict in idual chemical compounds in the three plant parts. Using principal components analysis (PCA) on the spectral data, we differentiated between treated and untreated s les for the in idual plant parts. Based on partial least squares–discriminant analysis (PLS-DA) models, the best discrimination of treated from non-treated s les with the smallest root mean square error cross-validation (RMSECV) and highest coefficient of determination (r 2 ) was achieved in the fresh needles (r 2 = 0.81, RMSECV= 0.24) and fresh inner bark (r 2 = 0.79, RMSECV = 0.25) for MJ-treated s les 14 days and 21 days after treatment, respectively. Using partial least squares regression, models for in idual compounds gave high (r 2 ), residual predictive deviation (RPD), lab to NIR error (PRL) or range error ratio (RER) for fructose (r 2 = 0.84, RPD = 1.5, PRL = 0.71, RER = 7.25) and glucose (r 2 = 0.83, RPD = 1.9, PRL = 1.14, RER = 8.50) and several diterpenoids. This provides an optimistic outlook for the use of NIR spectroscopy-based models for the larger-scale prediction of the P. radiata chemistry needed for quantitative genetic studies.

A water availability gradient reveals the deficit level required to affect traits in potted juvenile Eucalyptus globulus

Publisher: Oxford University Press (OUP)

Date: 10-01-2017

DOI: 10.1093/AOB/MCW266

Phylogenetic trait conservatism predicts patterns of plant‐soil feedback

Publisher: Wiley

Date: 10-2018

DOI: 10.1002/ECS2.2409

The Extended Community-Level Effects of Genetic Variation in Foliar Wax Chemistry in the Forest Tree Eucalyptus globulus

Publisher: Springer Science and Business Media LLC

Date: 05-2017

DOI: 10.1007/S10886-017-0849-5

Abstract: Genetic variation in foundation trees can influence dependent communities, but little is known about the mechanisms driving these extended genetic effects. We studied the potential chemical drivers of genetic variation in the dependent foliar community of the focal tree Eucalyptus globulus. We focus on the role of cuticular waxes and compare the effects to that of the terpenes, a well-studied group of secondary compounds known to be bioactive in eucalypts. The canopy community was quantified based on the abundance of thirty-nine distinctive arthropod and fungal symptoms on foliar s les collected from canopies of 246 progeny from 13 E. globulus sub-races grown in a common garden trial. Cuticular waxes and foliar terpenes were quantified using gas chromatography - mass spectrometry (GC-MC). A total of 4 of the 13 quantified waxes and 7 of the 16 quantified terpenes were significantly associated with the dependent foliar community. Variation in waxes explained 22.9% of the community variation among sub-races, which was equivalent to that explained by terpenes. In combination, waxes and terpenes explained 35% of the genetic variation among sub-races. Only a small proportion of wax and terpene compounds showing statistically significant differences among sub-races were implicated in community level effects. The few significant waxes have previously shown evidence of ergent selection in E. globulus, which signals that adaptive variation in phenotypic traits may have extended effects. While highlighting the role of the understudied cuticular waxes, this study demonstrates the complexity of factors likely to lead to community genetic effects in foundation trees.

Do multiple herbivores maintain chemical diversity of Scots pine monoterpenes?

Publisher: The Royal Society

Date: 12-05-2011

DOI: 10.1098/RSTB.2010.0236

Abstract: A central issue in our understanding of the evolution of the ersity of plant secondary metabolites (PSMs) is whether or not compounds are functional, conferring an advantage to the plant, or non-functional. We examine the hypothesis that the ersity of monoterpene PSMs within a plant species (Scots pine Pinus sylvestris ) may be explained by different compounds acting as defences against high-impact herbivores operating at different life stages. We also hypothesize that pairwise coevolution, with uncorrelated interactions, is more likely to result in greater PSM ersity, than diffuse coevolution. We tested whether up to 13 different monoterpenes in Scots pine were inhibitory to herbivory by slugs ( Arion ater ), bank voles ( Clethrionomys glareolus ), red deer ( Cervus elaphus ) and capercaillie ( Tetrao urogallus) , each of which attack trees at a different life stage. Plants containing more α-pinene were avoided by both slugs and capercaillie, which may act as reinforcing selective agents for this dominant defensive compound. Herbivory by red deer and capercaillie were, respectively, weakly negatively associated with δ 3 -carene, and strongly negatively correlated with the minor compound β-ocimene. Three of the four herbivores are probably contributory selective agents on some of the terpenes, and thus maintain some, but by no means all, of the phytochemical ersity in the species. The correlated defensive function of α-pinene against slugs and capercaillie is consistent with diffuse coevolutionary processes.

Assessment and implications of intraspecific and phenological variability in monoterpenes of scots pine (Pinus sylvestris) foliage

Publisher: Springer Science and Business Media LLC

Date: 02-2007

DOI: 10.1007/S10886-006-9244-3

Abstract: Scots pine populations contain in iduals with widely differing amounts and composition of monoterpenes and exist as one of two chemotypes: with or without delta3-carene. We investigated the significance for ecological studies of two types of variation in monoterpenes: (1) the inherent variability in the concentration of monoterpenes or their relative amounts in needles of seedlings, saplings, and mature trees and (2) phenological variation in developing needles. The relative composition of needle monoterpenes in 5-year-old saplings changed during the needle development period until the final composition was reached upon needle maturity. Changes in composition depended on chemotype. Needles of the "no-delta3-carene" chemotype had higher absolute concentrations of alpha-pinene, beta-pinene, c hene, and total monoterpenes than "delta3-carene" chemotype. For the "delta3-carene" chemotype, the relative concentration of delta3-carene during the needle growing season and immediately after emergence of seedlings was higher compared to that reached at needle maturity. Repeated removal of single needles (at weekly intervals during growth) from 5-year-old saplings did not influence the composition of monoterpenes. Within a natural Scots pine dominated woodland, 18% of mature Scots pines (N=574) belonged to the "no-delta3-carene" chemotype. Chemotypic variation within populations means that the statistical power with which differences in monoterpene concentrations can be detected is lower when s ling from the whole population compared to s ling within chemotypes. Reduction of this background variation and accounting for chiral variation if present, would significantly aid efficiency, interpretation, and understanding of processes in chemical and ecological research. One method for achieving this is the screening of plants for chemotypes before the establishment of experiments or field s ling regimes. We present a summary of suitable analytical methods for needle tissue that facilitates this prior screening.

Stability of Plant Defensive Traits Among Populations in Two Eucalyptus Species Under Elevated Carbon Dioxide

Publisher: Springer Science and Business Media LLC

Date: 02-2012

DOI: 10.1007/S10886-012-0071-4

Abstract: Plant secondary metabolites (PSMs) mediate a wide range of ecological interactions. Investigating the effect of environment on PSM production is important for our understanding of how plants will adapt to large scale environmental change, and the extended effects on communities and ecosystems. We explored the production of PSMs under elevated atmospheric carbon dioxide ([CO(2)]) in the species rich, ecologically and commercially important genus Eucalyptus. Seedlings from multiple Eucalyptus globulus and E. pauciflora populations were grown in common glasshouse gardens under elevated or ambient [CO(2)]. Variation in primary and secondary chemistry was determined as a function of genotype and treatment. There were clear population differences in PSM expression in each species. Elevated [CO(2)] did not affect concentrations of in idual PSMs, total phenolics, condensed tannins or the total oil yield, and there was no population by [CO(2)] treatment interaction for any traits. Multivariate analysis revealed similar results with significant variation in concentrations of E. pauciflora oil components between populations. A [CO(2)] treatment effect was detected within populations but no interactions were found between elevated [CO(2)] and population. These eucalypt seedlings appear to be largely unresponsive to elevated [CO(2)], indicating stronger genetic than environmental (elevated [CO(2)]) control of expression of PSMs.

Variation in constitutive and induced chemistry in the needles, bark and roots of young Pinus radiata trees

Publisher: Springer Science and Business Media LLC

Date: 23-09-2022

DOI: 10.1007/S00468-021-02209-5

Evolutionary History and Novel Biotic Interactions Determine Plant Responses to Elevated CO2 and Nitrogen Fertilization

Publisher: Public Library of Science (PLoS)

Date: 05-12-2014

DOI: 10.1371/JOURNAL.PONE.0114596

Effect of limited water availability on foliar plant secondary metabolites of two Eucalyptus species

Publisher: Elsevier BV

Date: 09-2014

DOI: 10.1016/J.ENVEXPBOT.2014.04.008

Quality traits of plantation Eucalyptus nitens logs impacting volume and value recovery of structural sawn boards

Publisher: Springer Science and Business Media LLC

Date: 15-02-2022

DOI: 10.1007/S00107-022-01790-X

Abstract: Plantations of Eucalyptus species are planted and grown worldwide for short rotations and with limited silvicultural treatments mostly to produce pulplogs for the pulp and paper industry. These resources could be used as raw material for construction timber, to support the increasing need of renewable resources from the building sector. To use fast-grown Eucalyptus logs as a source of sawn timber log grading standards are needed, which can be developed accounting for log characteristics impacting sawn timber recovery. This study aims to examine the quality of fast-grown Eucalyptus logs and relate relevant log quality traits to sawn timber characteristics. Wood quality and log characteristics of forty-nine fast-grown Eucalyptus logs and the characteristics and structural properties of 268 sawn boards milled from those logs were investigated. Significant differences were found in wood quality characteristics from logs sourced from different positions in the stem. However, sawn boards did not differ in their wood quality traits according to log position, which influenced only the amount and type of knots on the board surface and some structural properties. Moreover, log characteristics including volume, taper, log end splits and stiffness significantly impacted important board recovery traits. The results of this study show that log characteristics such as volume, taper, log end splits and stiffness should be accounted for in log grading standards seeking to grade fast-grown Eucalyptus resources for different product classes.

Quantitative trait loci for key defensive compounds affecting herbivory of eucalypts in Australia

Publisher: Wiley

Date: 25-03-2008

DOI: 10.1111/J.1469-8137.2008.02417.X

Abstract: * Formylated phloroglucinols (FPCs) are key defensive compounds that influence herbivory by mammals and arthropods in eucalypts. However, the genetic architecture underlying variation in their levels remains poorly understood. * Quantitative trait loci (QTL) analysis for the concentrations of two major FPCs, sideroxylonal A and macrocarpal G, was conducted using juvenile leaves from 112 clonally duplicated progenies from an outcross F2 of Eucalyptus globulus. * Two unlinked QTL were located for macrocarpal, while another unlinked QTL was located for sideroxylonal. The sideroxylonal QTL collocated with one for total sideroxylonal previously reported using adult Eucalyptus nitens foliage, providing independent validation in a different evolutionary lineage and a different ontogenetic stage. * Given the potential widespread occurrence of these QTL, their ontogenetic stability, and their impact on a range of dependent herbivores, it is possible that they have extended phenotypic effects in the Australian forest landscape.

Chemical Traits that Predict Susceptibility of Pinus radiata to Marsupial Bark Stripping

Publisher: Springer Science and Business Media LLC

Date: 06-10-2022

DOI: 10.1007/S10886-021-01307-5

Abstract: Bark stripping by mammals is a major problem in managed conifer forests worldwide. In Australia, bark stripping in the exotic plantations of Pinus radiata is mainly caused by native marsupials and results in reduced survival, growth, and in extreme cases death of trees. Herbivory is influenced by a balance between primary metabolites that are sources of nutrition and secondary metabolites that act as defences. Identifying the compounds that influence herbivory may be a useful tool in the management of forest systems. This study aimed to detect and identify both constitutive and induced compounds that are associated with genetic differences in susceptibility of two-year-old P. radiata trees to bark stripping by marsupials. An untargeted profiling of 83 primary and secondary compounds of the needles and bark s les from 21 susceptible and 21 resistant families was undertaken. These were among the most and least damaged families, respectively, screened in a trial of 74 families that were exposed to natural field bark stripping by marsupials. Experimental plants were in the same field trial but protected from bark stripping and a subset were subjected to artificial bark stripping to examine induced and constitutive chemistry differences between resistant and susceptible families. Machine learning (random forest), partial least squares plus discriminant analysis (PLS-DA), and principal components analysis with discriminant analysis (PCA-DA), as well as univariate methods were used to identify the most important totals by compound group and in idual compounds differentiating the resistant and susceptible families. In the bark, the constitutive amount of two sesquiterpenoids - bicyclogermacrene and an unknown sesquiterpenoid alcohol -were shown to be of higher levels in the resistant families, whereas the constitutive sugars, fructose, and glucose, as well in idual phenolics, were higher in the more susceptible families. The chemistry of the needles was not useful in differentiating the resistant and susceptible families to marsupial bark stripping. After artificial bark stripping, the terpenes, sugars, and phenolics responded in both the resistant and susceptible families by increasing or reducing amounts, which leveled the differences in the amounts of the compounds between the different resistant and susceptible classes observed at the constitutive level. Overall, based on the families with extreme values for less and more susceptibility, differences in the amounts of secondary compounds were subtle and susceptibility due to sugars may outweigh defence as the cause of the genetic variation in bark stripping observed in this non-native tree herbivory system.

Responses to mild water deficit and rewatering differ among secondary metabolites but are similar among provenances within Eucalyptus species

Publisher: Oxford University Press (OUP)

Date: 23-10-2015

DOI: 10.1093/TREEPHYS/TPV106

Abstract: Water deficit associated with drought can severely affect plants and influence ecological interactions involving plant secondary metabolites. We tested the effect of mild water deficit and rewatering on physiological, morphological and chemical traits of juvenile Eucalyptus globulus Labill. and Eucalyptus viminalis Labill. We also tested if responses of juvenile eucalypts to water deficit and rewatering varied within species using provenances across a rainfall gradient. Both species and all provenances were similarly affected by mild water deficit and rewatering, as only foliar abscisic acid levels differed among provenances during water deficit. Across species and provenances, water deficit decreased leaf water potential, above-ground biomass and formylated phloroglucinol compound concentrations, and increased condensed tannin concentrations. Rewatering reduced leaf carbon : nitrogen, and total phenolic and chlorogenic acid concentrations. Water deficit and rewatering had no effect on total oil or in idual terpene concentrations. Levels of trait plasticity due to water deficit and rewatering were less than levels of constitutive trait variation among provenances. The overall uniformity of responses to the treatments regardless of native provenance indicates limited ersification of plastic responses when compared with the larger quantitative variation of constitutive traits within these species. These responses to mild water deficit may differ from responses to more extreme water deficit or to responses of juvenile/mature eucalypts growing at each locality.

Quantitative trait loci for foliar terpenes in a global eucalypt species

Publisher: Springer Science and Business Media LLC

Date: 16-11-2011

DOI: 10.1007/S11295-010-0350-6

New frontiers in community and ecosystem genetics for theory, conservation, and management

Publisher: Wiley

Date: 02-12-2011

DOI: 10.1111/J.1469-8137.2011.03973.X

Development of Non-Destructive-Testing Based Selection and Grading Strategies for Plantation Eucalyptus nitens Sawn Boards

Publisher: MDPI AG

Date: 15-03-2021

DOI: 10.3390/F12030343

Abstract: Stiffness is considered one of the most important structural properties for sawn timber used in buildings and laminated structures including mass timber elements. There is great potential to use plantation Eucalyptus timber for structural applications, and the successful development of a plantation timber supply chain for structural products will depend on the accurate selection and grading of the resource. In this study we aimed to investigate the suitability of non-destructive testing (NDT) to improve selection and grading of sawn boards sourced from a young E. nitens plantation. We studied 268 sawn boards traced from the tree through to final processing stages. We found high and positive correlations between stiffness (measured as dynamic modulus of elasticity) tested at each board processing stage through acoustic wave velocity (AWV) and the static board modulus of elasticity measured through mechanical testing on dressed boards. Position of the board in the stem and sawn board processing treatment significantly impacted board modulus of elasticity, indicating that early selection of logs would allow larger yield of stiffer boards. We investigated the grading of boards through the traditional Australian Standards using a visual-grading system and through AWV, finding a classification error of 82.5% and 45.2%, respectively. We developed a linear model which was used to re-classify the boards, obtaining a smaller classification error, including fewer boards being over-graded. Our results demonstrate that AWV can be used as an early selection method for structural boards and can also be employed to satisfactorily grade E. nitens plantation boards to be used in building structures and as elements of mass timber.

Forest fire may disrupt plant–microbial feedbacks

Publisher: Springer Science and Business Media LLC

Date: 21-02-2018

DOI: 10.1007/S11258-018-0811-9

Genetic control of cuticular wax compounds in Eucalyptus globulus

Publisher: Wiley

Date: 11-08-2016

DOI: 10.1111/NPH.13600

Abstract: Plant cuticular wax compounds perform functions that are essential for the survival of terrestrial plants. Despite their importance, the genetic control of these compounds is poorly understood outside of model taxa. Here we investigate the genetic basis of variation in cuticular compounds in Eucalyptus globulus using quantitative genetic and quantitative trait loci ( QTL ) analyses. Quantitative genetic analysis was conducted using 246 open‐pollinated progeny from 13 native sub‐races throughout the geographic range. QTL analysis was conducted using 112 clonally replicated progeny from an outcross F 2 population. Nine compounds exhibited significant genetic variation among sub‐races with three exhibiting signals of ersifying selection. Fifty‐two QTL were found with co‐location of QTL for related compounds commonly observed. Notable among these was the QTL for five wax esters, which co‐located with a gene from the KCS family, previously implicated in the biosynthesis of cuticular waxes in Arabidopsis. In combination, the QTL and quantitative genetic analyses suggest the variation and differentiation in cuticular wax compounds within E. globulus has a complex genetic origin. Sub‐races exhibited independent latitudinal and longitudinal differentiation in cuticular wax compounds, likely reflecting processes such as historic gene flow and ersifying selection acting upon genes that have erse functions in distinct biochemical pathways.

Genetic analysis of the near-infrared spectral phenome of a global Eucalyptus species

Publisher: Springer Science and Business Media LLC

Date: 06-03-2013

DOI: 10.1007/S11295-013-0607-Y

Potential ‘costs of reproduction’ in a skink: Inter‐ and intrapopulational variation

Publisher: Wiley

Date: 04-2001

DOI: 10.1046/J.1442-9993.2001.01104.X

Friction correction when predicting wood basic density using drilling resistance

Publisher: Walter de Gruyter GmbH

Date: 29-10-2020

DOI: 10.1515/HF-2020-0156

Abstract: Basic density is a fundamental wood property of pulp and sawn wood. An IML Resi PD 400 drilling resistance tool (IML System GmbH, Wiesloch, Germany) was used to evaluate the basic density of Eucalyptus nitens discs and the impact of needle friction on basic density prediction. To determine the accuracy of that prediction with the commonly used linear drill bit shaft friction correction and determine whether this correction is linear, 40 discs were drilled radially, then cut into segments which were measured for basic density. Drilling resistance had a strong relationship with basic density in the outer wood it was weaker at the pith but this did not compromise prediction accuracy. When using a linear friction correction, the drilling resistance underpredicts basic density by 7.6% in the first 2–3 cm after stem entry, after which the prediction error ranged from 0.6–1.9%. The friction correction was found to be nonlinear, especially at the first few centimeters. To apply this friction correction, basic density values from the model should be added to predict basic density values until 2.9 cm from Resi entry point and after that subtracted to account for the drill bit shaft friction.

Thinning Influences Wood Properties of Plantation-Grown Eucalyptus nitens at Three Sites in Tasmania

Publisher: MDPI AG

Date: 24-09-2021

DOI: 10.3390/F12101304

Abstract: Thinning of forestry plantations is a common silviculture practice to increase growth rates and to produce larger dimension logs. The wood properties, basic density and stiffness, are key indicators of the suitability of timber for particular purposes and ultimately determine timber value. The impact of thinning operations on wood properties is, therefore, of considerable interest to forest growers and timber producers. To date, studies examining the impact of thinning on wood properties have produced variable results and understanding the consistency of the effects of thinning treatments across various sites for important plantation species is limited. Two non-destructive assessment techniques, drilling resistance and acoustic wave velocity, were used to examine the impact of thinning on basic density and stiffness in 19–21-year-old plantation grown Eucalyptus nitens across three sites. Commercial thinning to 300 trees ha−1 decreased the stiffness of standing trees and this effect was consistent across the sites. Reduction in stiffness due to thinning ranged from 3.5% to 11.5%. There was no difference in wood properties between commercially and non-commercially thinned trees to 300 trees ha−1 and no difference in wood properties when thinned to 500 trees ha−1. Basic density was not affected by thinning. The site had significant effects on both basic density and stiffness, which were lowest at the highest precipitation and highest elevation site. The results indicate that wood properties are influenced both by silviculture and site environmental differences. This knowledge can be used for the better management of E. nitens resources for solid wood production.

Native plant/herbivore interactions as determinants of the ecological and evolutionary effects of invasive mammalian herbivores: The case of the common brushtail possum

Publisher: Springer Science and Business Media LLC

Date: 05-11-2010

DOI: 10.1007/S10530-009-9629-7

Genetic correlations in multi-species plant/herbivore interactions at multiple genetic scales. Implications for eco-evolutionary dynamics

Publisher: Elsevier

Date: 2014

DOI: 10.1016/B978-0-12-801374-8.00008-6

Mammalian herbivores reveal marked genetic divergence among populations of an endangered plant species

Publisher: Wiley

Date: 13-07-2012

DOI: 10.1111/J.1600-0706.2011.19667.X

Genetic variation in fire recovery and other fire-related traits in a global eucalypt species

Publisher: Springer Science and Business Media LLC

Date: 12-11-2022

DOI: 10.1007/S11295-022-01572-9

Abstract: To understand the potential of forests to adapt to wildfire, we studied the genetic architecture of fire-related structural, damage and recovery traits in a globally important Australian forest tree species, Eucalyptus globulus . Fourteen traits were evaluated in an outcrossed F 2 population in a field trial in Tasmania, Australia, which was burnt by a wildfire 14 years after planting. The trial also included open-pollinated families of the grandparental dwarf and tall ecotypes used to produce the F 2 population. We studied the phenotypic correlations within the F 2 population and performed quantitative trait loci (QTL) analyses using a linkage map comprised of 472 markers. Ecotype comparisons revealed that almost all traits were under genetic control, with trees of the dwarf ecotype significantly more damaged and mainly recovering from lignotubers, whereas tall ecotype trees mainly recovered from epicormic resprouts extending for a variable height up the stem. Within the F 2 , tree size was negatively correlated with fire damage and positively correlated with recovery. Genetic control of fire-related traits was confirmed by the detection of 38 QTL in the F 2 population. These QTL accounted for 4 to 43% of the phenotypic variation in these traits. Several QTL co-located and likely reflect pleiotropic effects. However, many independent QTL were detected, including QTL for crown consumption and trunk scorch, epicormic resprouting, resprout herbivory, and seedling establishment. The QTL detected argue that many genetically controlled mechanisms are responsible for variation in fire damage and recovery.

Damage to and intake of plantation seedlings by captive European rabbits ( Oryctolagus cuniculus)

Publisher: Informa UK Limited

Date: 2000

DOI: 10.1080/00049158.2000.10674807

Linking plant genotype, plant defensive chemistry and mammal browsing in a Eucalyptus species

Publisher: Wiley

Date: 21-09-2004

DOI: 10.1111/J.0269-8463.2004.00887.X

Genomic selection for resistance to mammalian bark stripping and associated chemical compounds in radiata pine

Publisher: Oxford University Press (OUP)

Date: 11-10-2022

DOI: 10.1093/G3JOURNAL/JKAC245

Abstract: The integration of genomic data into genetic evaluations can facilitate the rapid selection of superior genotypes and accelerate the breeding cycle in trees. In this study, 390 trees from 74 control-pollinated families were genotyped using a 36K Axiom SNP array. A total of 15,624 high-quality SNPs were used to develop genomic prediction models for mammalian bark stripping, tree height, and selected primary and secondary chemical compounds in the bark. Genetic parameters from different genomic prediction methods—single-trait best linear unbiased prediction based on a marker-based relationship matrix (genomic best linear unbiased prediction), multitrait single-step genomic best linear unbiased prediction, which integrated the marker-based and pedigree-based relationship matrices (single-step genomic best linear unbiased prediction) and the single-trait generalized ridge regression—were compared to equivalent single- or multitrait pedigree-based approaches (ABLUP). The influence of the statistical distribution of data on the genetic parameters was assessed. Results indicated that the heritability estimates were increased nearly 2-fold with genomic models compared to the equivalent pedigree-based models. Predictive accuracy of the single-step genomic best linear unbiased prediction was higher than the ABLUP for most traits. Allowing for heterogeneity in marker effects through the use of generalized ridge regression did not markedly improve predictive ability over genomic best linear unbiased prediction, arguing that most of the chemical traits are modulated by many genes with small effects. Overall, the traits with low pedigree-based heritability benefited more from genomic models compared to the traits with high pedigree-based heritability. There was no evidence that data skewness or the presence of outliers affected the genomic or pedigree-based genetic estimates.

Phylogeny Explains Variation in The Root Chemistry of Eucalyptus Species

Publisher: Springer Science and Business Media LLC

Date: 30-08-2016

DOI: 10.1007/S10886-016-0750-7

Abstract: Plants are dependent on their root systems for survival, and thus are defended from belowground enemies by a range of strategies, including plant secondary metabolites (PSMs). These compounds vary among species, and an understanding of this variation may provide generality in predicting the susceptibility of forest trees to belowground enemies and the quality of their organic matter input to soil. Here, we investigated phylogenetic patterns in the root chemistry of species within the genus Eucalyptus. Given the known ersity of PSMs in eucalypt foliage, we hypothesized that (i) the range and concentrations of PSMs and carbohydrates in roots vary among Eucalyptus species, and (ii) that phylogenetic relationships explain a significant component of this variation. To test for interspecific variation in root chemistry and the influence of tree phylogeny, we grew 24 Eucalyptus species representing two subgenera (Eucalyptus and Symphyomyrtus) in a common garden for two years. Fine root s les were collected from each species and analyzed for total phenolics, condensed tannins, carbohydrates, terpenes, and formylated phloroglucinol compounds. Compounds displaying significant interspecific variation were mapped onto a molecular phylogeny and tested for phylogenetic signal. Although all targeted groups of compounds were present, we found that phenolics dominated root defenses and that all phenolic traits displayed significant interspecific variation. Further, these compounds displayed a significant phylogenetic signal. Overall, our results suggest that within these representatives of genus Eucalyptus, more closely related species have more similar root chemistry, which may influence their susceptibility to belowground enemies and soil organic matter accrual.

Development of a segregation method to sort fast-grown Eucalyptus nitens (H. Deane & Maiden) Maiden plantation trees and logs for higher quality structural timber products

Publisher: Springer Science and Business Media LLC

Date: 22-03-2022

DOI: 10.1186/S13595-022-01122-2

Abstract: A method to segregate trees and logs of planted Eucalyptus nitens (H. Deane & Maiden) Maiden has been developed, showing that accounting for wood quality during the process of segregation and sorting of timber resources allows for the recovery of structural timber of the desired quality. Appropriate sorting of raw forest resources is necessary to allocate logs to different production streams, to ensure that the desired quality of timber is achieved. Acoustic wave velocity can be used to test the wood quality of trees and logs, and its use as a sorting tool needs to be investigated prior to the development of a segregation method to recover high-quality timber. This study aimed to develop a segregation methodology for plantation E. nitens trees and logs to obtain high-quality structural boards. Forty-nine logs of planted E. nitens were measured, assessed with acoustic wave velocity, and processed into 268 structural boards maintaining board, log, and tree identity. Board stiffness was determined via structural testing and boards were ranked in structural grades. Linear mixed effect models were used to predict board stiffness based on tree and log variables, and machine learning decision trees were used to create a segregation method for board grades. Different segregation options were compared through scenario simulation. The prediction of in idual board stiffness with tree or log variables yielded low coefficients of variation due to large intra-log variability ( R 2 = 0.22 for tree variables and R 2 = 0.28 for log variables). However, the decision tree identified acoustic wave velocity thresholds to segregate E. nitens trees and logs. When applied in scenario simulation, segregation based on log variables produced the best results, resulting in large shares of high-quality board grades, showing that a segregation method based on wood quality traits can yield larger higher recovery of higher quality timber, in respect to other scenarios. Acoustic wave velocity can be used to segregate trees and logs for structural boards from plantation E. nitens , and machine learning decision trees can support the development of a segregation method to determine operational thresholds to increase the recovery of high-quality timber.

Consistent community genetic effects in the context of strong environmental and temporal variation in Eucalyptus

Publisher: Springer Science and Business Media LLC

Date: 20-01-2021

DOI: 10.1007/S00442-020-04835-1

Chemical Variation in a Dominant Tree Species: Population Divergence, Selection and Genetic Stability across Environments

Publisher: Public Library of Science (PLoS)

Date: 20-03-2013

DOI: 10.1371/JOURNAL.PONE.0058416

Genetic stability of physiological responses to defoliation in a eucalypt and altered chemical defence in regrowth foliage

Publisher: Oxford University Press (OUP)

Date: 22-11-2016

DOI: 10.1093/TREEPHYS/TPW101

Abstract: Defoliation may initiate physiological recovery and chemical defence mechanisms that allow a plant to improve fitness after damage. Such responses may result in changes in plant resource allocation that influence growth and foliar chemistry. In this study, we investigated the nature and stability of the defoliation response of juvenile plants from three ergent populations of Eucalyptus globulus Labill. A partial defoliation treatment that removed all upper crown leaves and the apical buds was applied to plants sourced from eight families from each of three populations representing contrasting chemical resistance to mammalian herbivory. Growth, photosynthetic rate and chlorophyll content were assessed pre-defoliation and periodically up to 12 weeks post-defoliation. The content of key plant primary and secondary metabolites was assessed pre-defoliation, at 12 weeks post-defoliation in the old foliage (positioned below the point of defoliation) and in the new foliage of the control plants and regrowth (from axillary buds) on the defoliated plants. There were clear treatment impacts on physiological responses, growth and foliar chemical traits, but despite significant constitutive differences in physiology, growth and chemistry the three E. globulus populations did not vary in their response to foliage loss. Distinct physiological responses to defoliation were observed with treatment plants showing significant up-regulation of photosynthetic rate and increased chlorophyll content in the old foliage remaining in the lower crown. There was a significant increase in the concentrations of a number of foliar chemical compounds in the regrowth arising from previously dormant axillary buds compared with new growth derived from apical meristems. There were changes in biomass allocation defoliated plants had increased branching and leaf biomass, with changes in regrowth morphology to increase light capture. This study argues for multiple responses of E. globulus juveniles to defoliation involving apical bud loss, including elevated chemical defences matched with increased growth. From a chemical defence perspective, these responses create an enhanced chemical mosaic to the herbivore, with leaves remaining after partial browsing potentially being more palatable than the regrowth. This study demonstrates the multiple independent strategies plants may use to respond to partial defoliation and emphasizes the dynamic interplay between growth and defence in the recovery response.

Additive genetic variation in Pinus radiata bark chemistry and the chemical traits associated with variation in mammalian bark stripping

Publisher: Springer Science and Business Media LLC

Date: 18-10-2021

DOI: 10.1038/S41437-021-00476-Z

A geographic mosaic of genetic variation within a foundation tree species and its community‐level consequences

Publisher: Wiley

Date: 07-2009

DOI: 10.1890/08-0951.1

Abstract: Knowledge of the manner in which genetic variation within a tree species affects associated communities and ecosystem processes across its entire range is important for understanding how geographic mosaics of genetic interactions might develop and support different communities. While numerous studies have investigated the community and ecosystem consequences of genetic variation at the hybrid cross type or genotype level within a species, none has investigated the community-level effects of intraspecific genetic variation across the geographic range of a widespread species. This is the scale at which geographic mosaics of coevolution are hypothesized to exist. Studies at this level are particularly important for foundation tree species, which typically support numerous microbial, fungal, plant, and animal communities. We studied genetic variation across eight geographical races of the forest tree Eucalyptus globulus representing its natural distribution across southeastern Australia. The study was conducted in a 15-year-old common garden trial based on families derived from single-tree open-pollinated seed collections from the wild. Neutral molecular genetic variation within E. globulus was also assessed and compared with genetic ergence in the phenotypic and community traits. Three major findings emerged. First, we found significant genetically based, hierarchical variation in associated communities corresponding to geographical races of E. globulus and families within races. Second, ergence in foliar communities at the racial level was associated with genetically based ergence in specific leaf morphological and chemical traits that have known defensive functions. Third, significant positive correlations between canopy community dissimilarity and both neutral molecular genetic and leaf quantitative genetic dissimilarity at the race level supported a genetic similarity rule. Our results argue that genetic variation within foundation tree species has the potential to be a significant driver of the geographical mosaics of variation typical of forest communities, which could have important ecological and evolutionary implications.

Pinus sylvestris sapling growth and recovery from mammalian browsing

Publisher: Elsevier BV

Date: 08-2014

DOI: 10.1016/J.FORECO.2014.03.038

Phylogenetic Responses of Forest Trees to Global Change

Publisher: Public Library of Science (PLoS)

Date: 04-04-2013

DOI: 10.1371/JOURNAL.PONE.0060088

Quantitative genetic variation in bark stripping of pinus radiata

Publisher: MDPI AG

Date: 18-12-2020

DOI: 10.3390/F11121356

Abstract: Bark stripping by mammals is a major problem for conifer forestry worldwide. In Australia, bark stripping in the exotic plantations of Pinus radiata is mainly caused by native marsupials. As a sustainable management option, we explored the extent to which natural variation in the susceptibility of P. radiata is under genetic control and is thus amenable to genetic improvement. Bark stripping was assessed at ages four and five years in two sister trials comprising 101 and 138 open-pollinated half-sib families. A third younger trial comprising 74 full-sib control-pollinated families was assessed at two and three years after planting. Significant additive genetic variation in bark stripping was demonstrated in all trials, with narrow-sense heritability estimates between 0.06 and 0.14. Within sites, the amount of additive genetic variation detected increased with the level of bark stripping. When strongly expressed across the two sister trials, the genetic signal was stable (i.e., there was little genotype × environment interaction). No significant non-additive effect (specific combining ability effect) on bark stripping was detected in the full-sib family trial, where it was estimated that up to 22.1% reduction in bark stripping might be achieved by selecting 20% of the less susceptible families. Physical traits that were genetically correlated, and likely influenced the amount of bark removed from the trees by the marsupials, appeared to depend upon tree age. In the older trials, these traits included bark features (presence of rough bark, rough bark height, and bark thickness), whereas in the younger trial where rough bark was not developed, it was the presence of obstructive branches or needles on the stem. In the younger trial, a positive genetic correlation between prior height and bark stripping was detected, suggesting that initially faster growing trees exhibit more bark stripping than slower growing trees but later develop rough bark faster and became less susceptible. While the presence of unexplained genetic variation after accounting for these physical factors suggests that other explanatory plant traits may be involved, such as chemical traits, overall the results indicate that selection for reduced susceptibility is possible, with potential genetic gains for deployment and breeding.

Characterisation of wood quality of Eucalyptus nitens plantations and predictive models of density and stiffness with site and tree characteristics

Publisher: Elsevier BV

Date: 07-2021

DOI: 10.1016/J.FORECO.2021.118992

Linking plant genotype, plant defensive chemistry and mammal browsing in a Eucalyptus species

Publisher: Wiley

Date: 21-09-2004

DOI: 10.1111/J.0269-8463.2004.00887.X

Non-lethal strategies to reduce browse damage in eucalypt plantations

Publisher: Elsevier BV

Date: 12-2009

DOI: 10.1016/J.FORECO.2009.09.040

Inheritance of resistance to mammalian herbivores and of plant defensive chemistry in a Eucalyptus species

Publisher: Springer Science and Business Media LLC

Date: 03-2005

DOI: 10.1007/S10886-005-2030-9

Abstract: Hybridization in plants provides an opportunity to investigate the patterns of inheritance of hybrid resistance to herbivores, and of the plant mechanisms conferring this resistance such as plant secondary metabolites. We investigated how inter-race differences in resistance of Eucalyptus globulus to a generalist mammalian herbivore, Trichosurus vulpecula, are inherited in their F1 hybrids. We assessed browsing damage of three-year-old trees in a common environment field trial on four hybrid types of known progeny. The progency were artificial intra-race crosses and reciprocal inter-race F1 hybrids of two geographically distinct populations (races) of E. globulus north-eastern Tasmania and south-eastern Tasmania. Populations of trees from north-eastern Tasmania are relatively susceptible to browsing by T. vulpecula, while populations from south-eastern Tasmania are more resistant. We assessed the preferences of these trees in a series of paired feeding trials with captive animals to test the field trial results and also investigated the patterns of inheritance of plant secondary metabolites. Our results demonstrated that the phenotypic expression of resistance of the inter-race F1 hybrids supported the additive pattern of inheritance, as these hybrids were intermediate in resistance compared to the pure parental hybrids. The expression of plant secondary metabolites in the F1 hybrids varied among groups of in idual compounds. The most common pattern supported was dominance towards one of the parental types. Together, condensed tannins and essential oils appeared to explain the observed patterns of resistance among the four hybrid types. While both chemical groups were inherited in a dominant manner in the inter-race F1 hybrids, the direction of dominance was opposite. Their combined concentration, however, was inherited in an additive manner, consistent with the phenotypic differences in browsing.

Analysis of the transcriptome of the needles and bark of Pinus radiata induced by bark stripping and methyl jasmonate

Publisher: Springer Science and Business Media LLC

Date: 13-01-2022

DOI: 10.1186/S12864-021-08231-8

Abstract: Plants are attacked by erse insect and mammalian herbivores and respond with different physical and chemical defences. Transcriptional changes underlie these phenotypic changes. Simulated herbivory has been used to study the transcriptional and other early regulation events of these plant responses. In this study, constitutive and induced transcriptional responses to artificial bark stripping are compared in the needles and the bark of Pinus radiata to the responses from application of the plant stressor, methyl jasmonate. The time progression of the responses was assessed over a 4-week period. Of the 6312 unique transcripts studied, 86.6% were differentially expressed between the needles and the bark prior to treatment. The most abundant constitutive transcripts were related to defence and photosynthesis and their expression did not differ between the needles and the bark. While no differential expression of transcripts were detected in the needles following bark stripping, in the bark this treatment caused an up-regulation and down-regulation of genes associated with primary and secondary metabolism. Methyl jasmonate treatment caused differential expression of transcripts in both the bark and the needles, with in idual genes related to primary metabolism more responsive than those associated with secondary metabolism. The up-regulation of genes related to sugar break-down and the repression of genes related with photosynthesis, following both treatments was consistent with the strong down-regulation of sugars that has been observed in the same population. Relative to the control, the treatments caused a differential expression of genes involved in signalling, photosynthesis, carbohydrate and lipid metabolism as well as defence and water stress. However, non-overlapping transcripts were detected between the needles and the bark, between treatments and at different times of assessment. Methyl jasmonate induced more transcriptional responses in the bark than bark stripping, although the peak of expression following both treatments was detected 7 days post treatment application. The effects of bark stripping were localised, and no systemic changes were detected in the needles. There are constitutive and induced differences in the needle and bark transcriptome of Pinus radiata . Some expression responses to bark stripping may differ from other biotic and abiotic stresses, which contributes to the understanding of plant molecular responses to erse stresses. Whether the gene expression changes are heritable and how they differ between resistant and susceptible families identified in earlier studies needs further investigation.

Effects of thinning on the longitudinal and radial variation in wood properties of Eucalyptus nitens

Publisher: Oxford University Press (OUP)

Date: 02-04-2022

DOI: 10.1093/FORESTRY/CPAC007

Abstract: Eucalypt plantations in Tasmania have been managed predominantly for fibre production, but there is also growing interest in the production of solid wood products. For solid wood production, stiffness and basic density are key wood properties as they define the suitability of the timber for particular products and ultimately value. To inform processing options available for targeting high value wood products there is a need to understand how wood properties vary within a tree and how thinning impacts wood quality to foster efficient processing. Three thinning trials of 20–22-year-old plantation grown Eucalyptus nitens were used to assess stiffness and basic density longitudinally from the base to 20 m height in the tree and radially at a fixed height of 2.5 m. Longitudinally and radially, wood properties varied more within the tree than the variation which arose as a result of thinning. Stiffness was lowest at the bottom of the tree irrespective of thinning treatment and the highest stiffness was located from 7.5 to 15 m height depending on thinning and site. Commercial thinning to 300 trees ha−1 had no effect on stiffness in the bottom of the tree but resulted in lower stiffness in the upper logs. Trees in thinned stands had slightly lower basic density and that reduction was consistent within the tree and across sites. Thinning resulted in significant radial change in wood properties and the thinning effect was apparent soon after the thinning treatment. The results demonstrate that thinning has an adverse impact on wood properties, but not to a degree that hinders the benefits thinning brings to maximizing wood growth. However, the high variation in wood quality within the tree suggests that it would be valuable segregating logs within a tree to maximize solid wood product value.

Population divergence in the ontogenetic trajectories of foliar terpenes of a Eucalyptus species

Publisher: Oxford University Press (OUP)

Date: 28-11-2015

DOI: 10.1093/AOB/MCU222

Direct and indirect effects of marsupial browsing on a foundation tree species

Publisher: Wiley

Date: 14-10-2015

DOI: 10.1111/OIK.01538

Potential ‘costs of reproduction’ in a skink: Inter‐ and intrapopulational variation

Publisher: Wiley

Date: 04-2001

DOI: 10.1046/J.1442-9993.2001.01104.X

Geographic and annual variation in reproductive cycles in the Tasmanian spotted snow skink, Niveoscincus ocellatus (Squamata : Scincidae)

Publisher: CSIRO Publishing

Date: 1999

DOI: 10.1071/ZO99038

Abstract: We studied the reproductive cycle of two populations of the spotted snow skink, Niveoscincus ocellatus, over a three-year period. This species is widespread in Tasmania and its distribution overlaps those of other species in the genus that show two distinct reproductive strategies: annual reproduction that is completed within one season, and biennial reproduction in which females carry advanced embryos throughout winter hibernation. We chose populations representative of the climatic extremes of the species’ distribution, within these areas of overlap. Niveoscincus ocellatus maintains the same basic reproductive strategy in both populations: summer gestation, primary autumn mating with obligate sperm storage by females, secondary mating in spring, and predominantly spring vitellogenesis and ovulation. In both populations all females reproduce annually, suggesting that reproductive frequency is not constrained by availability of energy. However, we found distinct differences in the timing of ovulation and parturition. Females from our subalpine site ovulated approximately one month later than those from our warmer, lowland site parturition was delayed by the same period so gestation length was unchanged. The delay in ovulation results in gestation proceeding over the warmest months at the cold site. The annual reproductive cycle of this species appears to constrain its distribution to the lower altitudinal/climatic range of alpine Niveoscincus species. There were minor annual differences in the timing of reproductive events at each site, which we attribute to variation in thermal conditions and the amount of precipitation.

Repellent and stocking guards reduce mammal browsing in eucalypt plantations

Publisher: Springer Science and Business Media LLC

Date: 17-02-2011

DOI: 10.1007/S11056-011-9253-0

Stability of Genetic-Based Defensive Chemistry Across Life Stages in a Eucalyptus Species

Publisher: Springer Science and Business Media LLC

Date: 09-10-2007

DOI: 10.1007/S10886-007-9366-2

Abstract: Defensive chemistry is a key plant fitness trait, and the investigation of the expression of plant secondary metabolites across life stages is important in understanding the lifetime evolutionary selection pressures on a plant. The expression of genetic-based differences in foliar defensive chemistry, known to influence mammalian herbivore preferences, was studied across two contrasting life phases of the heteroblastic tree, Eucalyptus globulus. With plants from different subraces of E. globulus growing in a field trial, we compared the levels of seven chemical constituents in adult and juvenile foliage from related coppiced plants. Defensive chemistry was generally higher in more vulnerable coppice foliage than adult foliage. Significant, genetic-based differences among subraces were detected for two key defensive chemicals, a sideroxylonal and a macrocarpal, and these differences were stable across life phases. In contrast, significant differences among subraces in adult leaf condensed tannins were not evident in the coppice because of the absence of this group of tannins in this foliage. These findings lend support to hypotheses that suggest condensed tannins may have evolved for reasons other than mammalian herbivore defense.

Genetic and Ontogenetic Variation in an Endangered Tree Structures Dependent Arthropod and Fungal Communities

Publisher: Public Library of Science (PLoS)

Date: 03-12-2014

DOI: 10.1371/JOURNAL.PONE.0114132

When ranges collide. Evolutionary history, phylogenetic community interactions, global change factors, and range size differentially affect plant productivity

Publisher: Elsevier

Date: 2014

DOI: 10.1016/B978-0-12-801374-8.00009-8

Geographic Variation in Age and Size at Maturity in a Small Australian Viviparous Skink

Publisher: American Society of Ichthyologists and Herpetologists (ASIH)

Date: 08-2001

DOI: 10.1643/0045-8511(2001)001[0646:GVIAAS]2.0.CO;2

The role of genetic and chemical variation of Pinus sylvestris seedlings in influencing slug herbivory

Publisher: Springer Science and Business Media LLC

Date: 16-12-2007

DOI: 10.1007/S00442-006-0628-4

Abstract: This study investigated the genetic and chemical basis of resistance of Pinus sylvestris seedlings to herbivory by a generalist mollusc, Arion ater. Using feeding trials with captive animals, we examined selective herbivory by A. ater of young P. sylvestris seedlings of different genotypes and correlated preferences with seedling monoterpene levels. We also investigated the feeding responses of A. ater to artificial diets laced with two monoterpenes, Delta(3)-carene and alpha-pinene. Logistic regression indicated that two factors were the best predictors of whether seedlings in the trial would be consumed. In idual slug variation (replicates) was the most significant factor in the model however, alpha-pinene concentration (also representing beta-pinene, Delta(3)-carene and total monoterpenes due to multicollinearity) of needles was also a significant factor. While A. ater did not select seedlings on the basis of family, seedlings not eaten were significantly higher in levels of alpha-pinene compared to seedlings that were consumed. We also demonstrated significant genetic variation in alpha-pinene concentration of seedlings between different families of P. sylvestris. Nitrogen and three morphological seedling characteristics (stem length, needle length and stem diameter) also showed significant genetic variation between P. sylvestris families. Artificial diets laced with high (5 mg g(-1) dry matter) quantities of either Delta(3)-carene or alpha-pinene, were eaten significantly less than control diets with no added monoterpenes, supporting the results of the seedling feeding trial. This study demonstrates that A. ater selectively feed on P. sylvestris seedlings and that this selection is based, in part, on the monoterpene concentration of seedlings. These results, coupled with significant genetic variation in alpha-pinene concentration of seedlings and evidence that slug herbivory is detrimental to P. sylvestris fitness, are discussed as possible evidence for A. ater as a selective force on the evolution of defensive chemistry in P. sylvestris.

Discrimination between seedlings of Eucalyptus globulus, E. nitens and their F₁ hybrid using near-infrared reflectance spectroscopy and foliar oil content

Publisher: Walter de Gruyter GmbH

Date: 12-2008

DOI: 10.1515/SG-2008-0040

Abstract: Identification of plant hybrids produced from closely related species can be difficult using morphological characteristics alone, particularly when identifying young seedlings. In this study, we compared the performance of three calibration models developed to discriminate between seedlings of Eucalyptus globulus, E. nitens and their first-generation hybrid using either foliar oil chemistry or near-infrared reflectance spectral data from fresh, whole leaves. Both oil and near-infrared reflectance spectroscopy (NIRS) models were developed using partial least-squares discriminant analysis and showed high classification accuracy, all correctly classifying more than 91% of s les in cross-validation. Additionally, we developed a larger, “global” and independently validated NIRS model specifically to discriminate between E. globulus and F 1 hybrid seedlings of different ages. This model correctly classified 98.1% of s les in cross-validation and 95.1% of s les from an independent test set. These results show that NIRS analysis of fresh, whole leaves can be used as a rapid and accurate alternative to chemical analysis for the purpose of hybrid identification.

Effects of nutrient variability on the genetic-based resistance of Eucalyptus globulus to a mammalian herbivore and on plant defensive chemistry

Publisher: Springer Science and Business Media LLC

Date: 04-12-2005

DOI: 10.1007/S00442-004-1769-Y

Abstract: Plant resistance to herbivores can be influenced not only by the independent effects of plant genotype and environmental variation, but by interactions between the two. The main aim of this study was to assess the effects of environmental variability (nutrient treatment) on the known genetic-based expression of resistance and defensive chemistry of Eucalyptus globulus to browsing by the generalist mammalian herbivore Trichosurus vulpecula. In a captive feeding trial, we measured intake of seedlings from one relatively resistant (Blue Gum Hill) and one relatively susceptible (St Helens) population of E. globulus grown under two nutrient treatments (no fertiliser, plus fertiliser). There was a significant genotypexfertiliser interaction effect on intake of E. globulus foliage by T. vulpecula, and the predicted genetic-based resistance of the two populations was expressed only for the non-fertilised treatment. Expression of resistance largely reflected the combined and inverse effects of nitrogen and condensed tannin concentrations. The expression of plant secondary metabolite concentration differed between compounds, but in all cases the effects of plant genotype and fertiliser treatment were independent. The formylated phloroglucinol compounds differed significantly between genotypes but not between fertiliser treatments. In contrast, the effect of plant genotype on the expression of condensed tannins was weak but they were significantly reduced by fertiliser. Essential oils were influenced by both plant genotype and fertiliser treatment and were significantly higher in the fertilised seedlings than in the non-fertilised seedlings. This study highlights interactive effects of plant genotype and environment in influencing the phenotypic expression of resistance in a eucalypt species to a mammalian browser. It also demonstrates that this interactive effect is the net result of independent effects of genotype and environment on plant chemistry and finally, that different groups of compounds within a plant can respond very differently to variation in environmental conditions.

Effectiveness of repellents for reducing damage to eucalypt seedlings by browsing mammals

Publisher: Informa UK Limited

Date: 2008

DOI: 10.1080/00049158.2008.10675049

Genetic variation in resistance of Eucalyptus globulus to marsupial browsers

Publisher: Springer Science and Business Media LLC

Date: 2002

DOI: 10.1007/S004420100797

Abstract: The evolution of plant defensive traits in response to selection pressures imposed by herbivores is central to co-evolutionary theory. To demonstrate the role of herbivores as selective agents on plant resistance there must be variability in plant resistance to herbivores within a plant population. This variability must be under genetic control, and the variability in plant resistant traits and consequently herbivore damage to plants must reflect variability in plant fitness. We used a common eucalypt species, Eucalyptus globulus, and two major mammalian herbivores, the common brushtail possum (Trichosurus vulpecula) and the red-bellied pademelon (Thylogale billardierii), as a system to investigate intraspecific variation in plant resistance to mammalian herbivores and to investigate if this variation has a genetic basis. We measured mammalian browsing damage on 2,302 in idual trees of E. globulus, from 563 families derived from range-wide native stand seed collections of known pedigree and grown in a common environment field trial. Using a selection of trees from the field trial we then conducted a feeding trial with captive herbivores to assess if the genetic variation in plant resistance in the field was reflected in feeding preferences of captive animals, as measured by relative intake. Results from the field trial showed significant genetic variation in plant resistance amongst races, localities and amongst different families. These results were consolidated in the captive trial with similar trends in genetic variation among E. globulus localities. Dry matter intake of foliage by Trichosurus vulpecula was consistently greater than that by Thylogale billardierii however, the intraspecific preferences of the two herbivores were significantly correlated.

Genetic variation in resistance of Eucalyptus globulus to marsupial browsers

Publisher: Springer Science and Business Media LLC

Date: 2002

DOI: 10.1007/S004420100797

Abstract: The evolution of plant defensive traits in response to selection pressures imposed by herbivores is central to co-evolutionary theory. To demonstrate the role of herbivores as selective agents on plant resistance there must be variability in plant resistance to herbivores within a plant population. This variability must be under genetic control, and the variability in plant resistant traits and consequently herbivore damage to plants must reflect variability in plant fitness. We used a common eucalypt species, Eucalyptus globulus, and two major mammalian herbivores, the common brushtail possum (Trichosurus vulpecula) and the red-bellied pademelon (Thylogale billardierii), as a system to investigate intraspecific variation in plant resistance to mammalian herbivores and to investigate if this variation has a genetic basis. We measured mammalian browsing damage on 2,302 in idual trees of E. globulus, from 563 families derived from range-wide native stand seed collections of known pedigree and grown in a common environment field trial. Using a selection of trees from the field trial we then conducted a feeding trial with captive herbivores to assess if the genetic variation in plant resistance in the field was reflected in feeding preferences of captive animals, as measured by relative intake. Results from the field trial showed significant genetic variation in plant resistance amongst races, localities and amongst different families. These results were consolidated in the captive trial with similar trends in genetic variation among E. globulus localities. Dry matter intake of foliage by Trichosurus vulpecula was consistently greater than that by Thylogale billardierii however, the intraspecific preferences of the two herbivores were significantly correlated.

Field screening for genetic-based susceptibility to mammalian browsing

Publisher: Elsevier BV

Date: 10-2011

DOI: 10.1016/J.FORECO.2011.06.051

Variable patterns of inheritance of ecologically important plant secondary metabolites in an inter-specific eucalypt hybrid

Publisher: Elsevier BV

Date: 04-2014

DOI: 10.1016/J.FORECO.2014.01.016

Inheritance of resistance to mammalian herbivores and of plant defensive chemistry in an Eucalyptus species

Publisher: Springer Science and Business Media LLC

Date: 02-2005

DOI: 10.1007/S10886-005-1346-9

Abstract: Hybridization in plants provides an opportunity to investigate the patterns of inheritance of hybrid resistance to herbivores, and of the plant mechanisms conferring this resistance such as plant secondary metabolites. We investigated how inter-race differences in resistance of Eucalyptus globulus to a generalist mammalian herbivore, Trichosurus vulpecula, are inherited in their Fl hybrids. We assessed browsing damage of 3-year-old trees in a common environment field trial on four hybrid types of known progeny. The progeny were artificial intra-race crosses and reciprocal inter-race F1 hybrids of two geographically distinct populations (races) of E. globulus north-eastern Tasmania and south-eastern Tasmania. Populations of trees from north-eastern Tasmania are relatively susceptible to browsing by T. vulpecula, while populations from south-eastern Tasmania are more resistant. We assessed the preferences of these trees in a series of paired feeding trials with captive animals to test the field trial results and also investigated the patterns of inheritance of plant secondary metabolites. Our results demonstrated that the phenotypic expression of resistance of the inter-race Fl hybrids supported the additive pattern of inheritance, as these hybrids were intermediate in resistance compared to the pure parental hybrids. The expression of plant secondary metabolites in the Fl hybrids varied among major groups of in idual compounds. The most common pattern supported was dominance towards one of the parental types. Together, condensed tannins and essential oils appeared to explain the observed patterns of resistance among the four hybrid types. While both chemical groups were inherited in a dominant manner in the inter-race Fl hybrids, the direction of dominance was opposite. Their combined concentration, however, was inherited in an additive manner, consistent with the phenotypic differences in browsing.

A footprint of tree‐genetics on the biota of the forest floor

Publisher: Wiley

Date: 30-11-2009

DOI: 10.1111/J.1600-0706.2009.17609.X

Nitrification potential in the rhizosphere of Australian native vegetation

Publisher: CSIRO Publishing

Date: 2017

DOI: 10.1071/SR16116

Abstract: The rhizosphere influences nutrient dynamics in soil mainly by altering microbial activity. The objective of this study was to evaluate the rhizosphere effect on nitrogen transformation in Australian native vegetation in relation to nitrification potential (NP). Microbial activity, NP, and nitrifiers (ammonia-oxidising bacteria, AOB) were compared between rhizosphere and non-rhizosphere soils of several Australian native vegetation under field conditions. These parameters were also measured with increasing distance from the rhizosphere of selected plant species using plant growth experiments. To examine the persistence of nitrification inhibitory activity of rhizosphere soil on non-rhizosphere soil, the soils were mixed at various ratios and examined for NP and AOB populations. The rhizosphere soil from all native vegetation (29 species) had higher microbial activity than non-rhizosphere soil, whereas 13 species showed very low NP in the rhizosphere when compared with non-rhizosphere soil. Nitrification potential and AOB populations obtained in the soil mixture were lower than the predicted values, indicating the persistence of a nitrification inhibitory effect of the rhizosphere soils on non-rhizosphere soils. In plant growth experiments the microbial activity decreased with increasing distance from rhizosphere, whereas the opposite was observed for NP and AOB populations, indicating the selective inhibition of nitrification process in the rhizosphere of the Australian native plants Scaevola albida, Chrysocephalum semipapposum, and Enteropogon acicularis. Some Australian native plants inhibited nitrification in their rhizosphere. We propose future studies on these selected plant species by identifying and characterising the nitrification inhibiting compounds and also the potential of nitrification inhibition in reducing nitrogen losses through nitrate leaching and nitrous oxide emission.

Survival and recovery of Eucalyptus globulus seedlings from severe defoliation

Publisher: Elsevier BV

Date: 11-2016

DOI: 10.1016/J.FORECO.2016.08.025

Wood Properties Characterisation of Thermo-Hydro Mechanical Treated Plantation and Native Tasmanian Timber Species

Publisher: MDPI AG

Date: 10-11-2020

DOI: 10.3390/F11111189

Abstract: Thermo-hydro mechanical (THM) treatments and thermo-treatments are used to improve the properties of wood species and enhance their uses without the application of chemicals. This work investigates and compares the effects of THM treatments on three timber species from Tasmania, Australia plantation fibre-grown shining gum (Eucalyptus nitens H. Deane and Maiden), plantation saw-log radiata pine (Pinus radiata D. Don) and native-grown saw-log timber of the common name Tasmanian oak (which can be any of E. regnans F. Muell, E. obliqua L’Hér and E. delegatensis L’Hér). Thin lamellae were compressed by means of THM treatment from 8 mm to a target final thickness of 5 mm to investigate the suitability for using THM-treated lamellas in engineered wood products. The springback, mass loss, set-recovery after soaking, dimensional changes, mechanical properties, and Brinell hardness were used to evaluate the effects of the treatment on the properties of the species. The results show a marked increase in density for all three species, with the largest increase presented by E. nitens (+53%) and the smallest by Tasmanian oak (+41%). E. nitens displayed improvements both in stiffness and strength, while stiffness decreased in P. radiata s les and strength in Tasmanian oak s les. E. nitens also displayed the largest improvement in hardness (+94%) with respect to untreated s les. P. radiata presented the largest springback whilst having the least mass loss. E. nitens and Tasmanian oak showed similar dimensional changes, whilst P. radiata timber had the largest thickness swelling and set-recovery due to the high water absorption (99%). This study reported the effects of THM treatments in less-known and commercially important timber species, demonstrating that the wood properties of a fibre-grown timber can be improved through the treatments, potentially increasing the utilisation of E. nitens for structural and higher quality timber applications.

University Of Tasmania

Location: Australia

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Linking Plant Genetics And Chemistry To Maximise Tree Production In The Softwood Industry

Start Date: 2014

End Date: 2020

Funder: Australian Research Council

Providing A Genetic Framework To Enhance The Success And Benefits From Forest Restoration And Carbon Plantings In Rural Landscapes

Start Date: 2012

End Date: 2015

Funder: Australian Research Council

Linking Environmental Stress In Pine Plantations To Bark Stripping By Browsers And Fungal Attack: Developing Novel Options For Management

Start Date: 2006

End Date: 2009

Funder: Australian Research Council

Purchase Of An Ultra-performance Liquid Chromatograph-triple Quadrupole Mass Spectrometer

Start Date: 2010

End Date: 2010

Funder: Australian Research Council

Does Aggregated Retention Provide Suitable Habitat For Mammal Conservation In Old Growth Forests?

Start Date: 2009

End Date: 2010

Funder: Winifred Violet Scott Charitable Trust

Impacts Of An Alternative Logging Practice, Aggregated Retention, On Two Native Rodents

Start Date: 2009

End Date: 2009

Funder: Trust of M.A. Ingram

Does Aggregated Retention Provide Suitable Habitat For Mammal Conservation In Old Growth Forests?

Start Date: 2008

End Date: 2010

Funder: Holsworth Wildlife Research Endowment

Linkage Projects - Grant ID: LP120200380

Start Date: 09-2012

End Date: 12-2017

Amount: $501,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP140100602

Start Date: 06-2015

End Date: 06-2020

Amount: $470,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP120102889

Start Date: 2012

End Date: 12-2016

Amount: $220,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0773686

Start Date: 2007

End Date: 12-2010

Amount: $375,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0669742

Start Date: 06-2006

End Date: 12-2009

Amount: $227,820.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0562415

Start Date: 07-2005

End Date: 04-2010

Amount: $302,000.00

Funder: Australian Research Council

Industrial Transformation Training Centres - Grant ID: IC150100004

Start Date: 11-2015

End Date: 11-2021

Amount: $3,630,239.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE100100015

Start Date: 2010

End Date: 12-2010

Amount: $200,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0451533

Start Date: 2004

End Date: 12-2007

Amount: $240,000.00

Funder: Australian Research Council