UVicSpace : Browsing by Supervisor "Aderkas, P. von"

Browsing by Supervisor "Aderkas, P. von"

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An assessment of Pinus contorta seed production in British Columbia: Geographic variation and dynamically-downscaled climate correlates from the Canadian Regional Climate Model
(2015-04-28) Lew, Alicia; Weaver, Andrew J.; Aderkas, P. von
Lodgepole pine (Pinus contorta Douglas ex Louden) is the most widespread pine in North America and the single most abundant tree species in British Columbia (BC). Its vast distribution, diversity and economic value make it an important species for timber harvest and subsequent reforestation. Climate change raises serious concerns over the adaptability and effective management of BC’s future forests. The majority of lodgepole pine seedlings requested for replanting are produced from seed obtained from wild stands, but the relationship between climate variation and the seed production of natural populations has yet to be assessed. The purpose of this study is to determine if variation in P. contorta seed yield is related to the climate of BC. Historical cone collection data were obtained from archived records of 1948 seedlots in 22 different natural stand seed planning zones (SPZs) of BC. Collections were made between 1963 and 2013 and seed yield (kg fresh seed/hL cone) was determined for each seedlot. First, natural variation in seed production of lodgepole pine was examined in 18 different SPZs. The Nass Skeena Transition (NST) represents a unique intersection between continental and maritime ecosystems and was found to have a significantly higher mean seed yield compared to all other zones, with the exception of Hudson Hope (HH). However, variance in seed yield for NST was found to be an order of magnitude higher than that of other SPZs, indicating that seed production in this region is exceptionally variable. These findings provide a valuable geographic baseline for the reproductive fitness of lodgepole pine, suggesting that climate adaptation and mitigation strategies for some areas of the province may need to be region-specific. In addition, the relationship between climate variation and the seed production of P. contorta in BC was evaluated. The climate of each region was described using dynamically-downscaled Global Circulation Model (GCM) and reanalysis climate output from the Canadian Regional Climate Model (CRCM). Annual, winter, and summer means were explored for each of the climate variables of interest: total precipitation (mm) and surface air temperature (°C). Temporal correlations between the mean annual seed yield anomaly and the anomaly of both climate variables were significant under a variety of climate schemes in a number of SPZs. Significant overall trends in climate variables were also captured using GCM-driven CRCM output. While these two analyses independently highlighted significant relationships between seed yield and climate, their joint implications were unclear. Shifts in the CRCM boundary conditions revealed that the results lacked robustness during the historical period, inhibiting the investigation of future projections. Ambiguous age ranges for each cone collection and temporal restrictions of the seed collection data may be partially responsible for these inconclusive results. Results from the first half of this thesis suggest that, with few exceptions, seed production is relatively stable across SPZs spanning a wide range of climate regimes. Thus, the investigation of the relationship between reproductive fitness and climate may be complicated by the extraordinary adaptability of lodgepole pine and the high genetic variation in natural populations.
Creating a somatic embryogenic system to study resistance traits to the white pine weevil (Pissodes strobi Peck.) in Sitka spruce (Picea sitchensis (Bong.) Carr).
(2011-06-09) Prior, Natalie Annastasia; Aderkas, P. von
A somatic embryogenic system was created using material from the British Columbia Ministry of Forests and Range’s Sitka Spruce (Picea sitchensis (Bong.) Carr) breeding program for resistance to the white pine weevil (Pissodes strobi Peck.). The goal was to provide a system that could aid in understanding the phenotypic and genotypic variation that exists in these traits. Embryogenic lines were derived from controlled crosses of parental genotypes previously ranked for the abundance of three physical bark traits: sclereid cells, constitutive resin canals and traumatic resin canals. The number of filled seeds per cone from controlled pollinations was low, with a mean of 9.4 ± 6.8 (mean ± SD), compared to open-pollinated material, which had greater than 40 seeds per cone. The mean induction rate (to embryogenic cultures) was 7 %, ranging from 0 % to 56 % by cross. Of 135 genotypes, 88.1 % produced mature embryos. The number of embryos produced varied by culture. Nearly all (44 of 45) genotypes germinated, with a mean germination rate of 80 %. The overall conversion rate of somatic embryos to plants was 5.5 %. A novel method of cryopreservation that used a temperature pretreatment but did not require dimethyl sulfoxide was tested. Embryogenic cultures were recovered from 31 % of genotypes (n = 112). Genotypic and phenotypic variation were observed during each stage of the somatic embryogenic process. This project demonstrated that somatic embryogenesis and cryopreservation can be used to create a system to study phenotypic and genotypic variation in Sitka spruce.
Douglas fir megagametophyte development in situ and in vitro
(2018-02-07) Chiwocha, Sheila; Aderkas, P. von
Megagametophyte development in situ and in vitro was investigated in Douglas fir to address the following questions: (1) Do endogenous levels of plant hormones change during megagametophyte development and are they associated with morphological changes? (2) Can megagametophytes be cultured prior to fertilization? (3) Can embryos be rescued from megagametophytes cultured soon after fertilization? A histochemical study of storage reserve deposition during megagametophyte development was performed with material isolated weekly for 11 weeks. Prior to fertilization, starch was detected in the neck cells of megagametophytes analyzed 9 weeks after pollination (WAP). During embryogenesis, starch was deposited in the central region of megagametophytes. Proteins and lipids were first detected in the prothallial cells in the periphery of megagametophytes isolated 14 and 15 WAP, respectively. With further development, starch was deposited in prothallial cells around the corrosion cavity, while proteins and lipids were spatially localized to prothallial cells in the periphery. In the embryo, starch accumulation was preferentially localized in the root cap and the embryonal suspensor cells at 17 WAP. A parallel study quantifying the endogenous levels of plant hormones: IAA, IAAsp, Z, ZR, iP, IPA, ABA and ABA-GE, in megagametophytes was performed. Hormones were extracted, purified and fractionated using HPLC. To correct for losses due to procedures, radiolabelled standards were added prior to extraction. The hormones were quantified using an ELISA method. On a dry weight basis, Z levels were highest in megagametophytes at the late central cell stage (8 WAP). During embryogenesis, Z levels peaked during week 13. ZR peaked twice at 13 and 17 WAP. The iP content of megagametophytes increased at 10, 13 and 17 WAP while iP.A concentration increased at 13 and 17 WAP. Prior to fertilization, the free LAA was highest in megagametophytes at 9 WAP. During embryogenesis, the major lA A accumulations occurred at I I ,13 and 15 WAP. lAAsp concentrations reached their highest levels at 10, 14 and 18 WAP. ABA content increased at 11, 13 and 17 WAP. In contrast, ABA-GE levels were relatively constant over the 11 weeks analyzed. Megagametophytes were isolated weekly from 7–10 WAP and cultured on a modified half-strength Litvay's medium supplemented with one of three auxins (NAA, IBA or 2,4-D) and a cytokinin (2 mg/L BAP). Each auxin was tested at three levels: 0.1, 1.0 or 10 mg/L. The objective was to determine whether the megagametophytes would continue to grow in culture. Megagametophytes increased in length after 9 and 18 days of culture. Auxin and cytokinin supplements had a significant effect on growth for material isolated 7 or 10 WAP. However, the viability of the archegonia rapidly declined on all the media tested. The most optimal treatment for each auxin type (BAP in combination with 0.1 mg/L NAA. 1.0 mg/L IBA or 1.0 mg/L 2.4-D) was used to initially culture pollinated megagametophytes in the embryo rescue experiment. After 21 days, megagametophytes were transferred to media containing ABA concentrations of 0.5, 20 or 40 μM. A majority of the rescued embryos were developmentally arrested at the globular stage. Only three embryos, containing over 30 cotyledons each, matured on ABA concentrations of 5, 20 or 40 μM. In conclusion, the prothallial cells of the pre-fertilization megagametophytes could be cultured for long periods and their growth was not dependent on the presence of viable archegonia. The endogenous levels of plant hormones varied with megagametophyte development and were associated with morphological changes. This information has implications for growing megagametophytes for in vitro fertilization and embryo rescue experiments. The endogenous levels of plant hormones could be used to design culture media for rescuing embryos resulting from in vitro fertilization in Douglas fir.
Exploring the mechanisms of Pacific oyster summer mortality in Baynes Sound aquaculture
(2020-09-08) Cowan, Malcolm; Aderkas, P. von; Pearce, Christopher Michael
In recent years, mortalities of unknown aetiology have occurred in Pacific oyster aquaculture in Baynes Sound, BC during the summer. Field studies were conducted to examine environmental, reproductive and microbial factors that could be contributing to these mortalities. In 2017, oysters were observed at three sites from July 5 to September 15. Each intertidal site had three modules containing seven stacked trays with 80 oysters per tray. Final mortalities ranged from 9.3 ± 1.9 to 38.8 ± 4.9% per module. The mortality per module correlated significantly with gonad length and the proportion of oysters that were female in a multiple linear regression model (R2=0.824, p=0.002). Vibrio aestuarianus, a well-documented pathogen of farmed Pacific oysters in France, was well represented in bacterial cultures from intertidal oysters in 2017 based on recA gene sequencing of 158 bacterial isolates. In 2018, juvenile Pacific oysters were monitored to characterize the onset of a summer mortality event in suspended culture. From May 11 to September 17, data on shell size, reproductive development, environmental conditions, and the microbial community of gill tissue was tracked at culture densities of 150, 300, 450, and 600 oysters tray-1. The onset of mortality was associated with a period of rapid growth, reproductive development, and elevated temperatures. Cumulative mortality per tray ranged from 34 to 75%, with the highest density trays having significantly lower mortality (p=0.023), smaller shell width (p=0.001), smaller shell length (p=0.002) and smaller gonad length (p=0.049) than the lowest density trays in a linear mixed-effects regression. Histology of oysters from August 12, during the mortality event, showed a mixed microbial infection in peripheral gill tissue. High-throughput sequencing of the 16S rRNA gene and qPCR of V. aestuarianus using species-specific recA primers suggest V. aestuarianus is temporally associated with summer mortality. Mortalities observed in 2017 and 2018 occurred in different age classes and with different oyster culture techniques, but all were associated with elevated water temperature, increased reproductive effort, and the presence of V. aestuarianus.
Functional analysis of proteins in the conifer ovular secretion
(2020-08-31) Coulter, Andrea Elizabeth; Aderkas, P. von
Almost all conifer ovules produce a liquid secretion as part of reproduction. This secretion, termed an ovular secretion, is produced during ovule receptivity and is involved in pollen capture and transport. Historically, examinations of the ovular secretion have focused on how they are part of pollination mechanisms. As a result, the chemical composition of the ovular secretion has not been examined systematically. Investigations into the constituents of the ovular secretion were limited to analyses for simple water soluble compounds such as sugars, minerals, amino acids and organic acids. More recently, the protein component of the secretion has been investigated using mass spectrometry-based proteomics. Proteins involved in processes such as carbohydrate modification, proteolysis, and defence have been identified in conifer ovular secretions. This biochemical complexity suggests a broader view of the function of the ovular secretion is warranted. However, protein identifications only provide putative information on function. Functional characterization of these proteins is needed in order to fully understand how they contribute to ovular secretion function. The research outlined in this dissertation describes the first functional characterizations of proteins found in conifer ovular secretions. Three proteins - invertase, chitinase, and thaumatin-like protein - were characterized in the ovular secretions of Douglas-fir (Pseudotsuga menziesii) and hybrid yew (Taxus × media). The Douglas-fir ovular secretion is capable of converting sucrose to glucose and fructose, confirming that invertases present in the secretion are functional. The invertase activity was maximal at pH 4.0. Activity was 77% of maximal at pH 4.5, the physiological pH. This indicates that post-secretory hydrolysis of sucrose occurs in situ in the Douglas-fir ovular secretion. Invertases in the ovular secretion are likely involved in controlling the movement of carbohydrates to developing pollen and could facilitate pollen selection. Chitinases present in the Douglas-fir ovular secretion are functional at physiological conditions. All three modes of chitinolytic activity, i.e. endochitinase, chitobiosidase and β-N-acetylglucosaminidase, were detected at physiological pH. β-N-acetylglucosaminidase activity was 80 % of maximal at physiological pH. Chitinases are pathogenesis-related proteins capable of hydrolysing chitin in fungal cell walls. These results suggest the ovular secretion is capable of defending the ovule against infection by phytopathogens. Thaumatin-like protein was immunolocalized to the cell wall and amyloplasts in Douglas-fir and yew nucellar tissue in a pattern consistent with a defensive role. It was also localized to the cell wall of fungal spores and germinating hyphae that were present in the micropyle of a yew ovule. These results provide additional evidence for an antifungal role for the ovular secretion. Functioning enzymes involved in pollen-ovule interactions and ovule defence are present in the conifer ovular secretion. The ovular secretion has functions beyond pollen capture. A revised functional model for the conifer ovular secretion is proposed.
Gymnosperm pollination drop proteins and their relation to function and phylogeny
(2008-06-10T22:44:36Z) Wagner, Rebecca Elizabeth; Aderkas, P. von
The pollination drop is a conservative pollination mechanism observed in all major gymnosperm taxa. Despite its ubiquity and essentiality to gymnosperm reproductive success, it remains poorly understood. Recent studies identifying conifer ovular secretion proteins have indicated a more complex role for ovular secretions than pollen receipt. We used a proteomics approach to analyze the pollination drops of four gymnosperm species (Juniperus communis (common juniper), Juniperus oxycedrus (prickly juniper), Chamaecyparis lawsoniana (Port Orford cedar), and Welwitschia mirabilis). Pollination drop proteins were separated by SDS-PAGE, and the most abundant proteins were analyzed by mass spectrometry and sequenced. Based on BLAST searching of combined amino acid sequences, several proteins were identified: an 83 kDa subtilisin-like proteinase, a 62 kDa glycosyl hydrolase, a 47.5 kDa glucan 1,3-ß-glucosidase precursor, a 30 kDa chitinase, and a 25 kDa thaumatin-like protein in J. connnunis; a 30 kDa chitinase, a 25 kDa thaumatin-like protein, and a 32.5 kDa glucanase-like protein in J. oxycedrus; an 83 kDa subtilisin-like proteinase, a 62 kDa (ß-D-glucan exohydrolase, a 47.5 kDa glucan 1,3-ß-glucosidase, and two 25 kDa thaumatin-like proteins in C. lawsoniana, and a 25 kDa chitinase in W. mirabilis. Gymnosperm phylogeny is a highly debated topic, particularly following the widespread adoption of molecular phylogenetic analyses which conflict with historical morphological phylogenies. The gymnosperms are a difficult group to classify because of their deep evolutionary history and lack of conservative features. Considering that the pollination drop is a highly conservative feature of gymnosperm reproduction, we propose that analysis of pollination drop protein (PDP) variation could be used as an alternative method to resolve gymnosperm phylogeny. PDP variation was analyzed at three taxonomic levels: genus, family, and gymnosperm clade. Based on variation in SDS-PAGE banding patterns, identified peptides, amino acid sequences, and protein identification, we conclude that PDP variation has a phylogenetic component. Further research is necessary to develop this method into a tool used to predict phylogenetic relationships. Based on protein identifications, there is strong evidence that the pollination drop functions in both pathogen defense and pollen development. The observation of hydrogen peroxide and peroxidase activity in the ovular secretions of J. communis, C. lawsoniana, Pseudotsuga menziesii (Douglas fir), and Larix x marschlinsii (hybrid larch) provided further support for the assumed functions of ovular secretions.
Improving germination in white spruce somatic embryos with desiccation and/or cold treatments
(2017-11-10) Pond, Sharon Elizabeth; Aderkas, P. von
Clonal propagation of white spruce (Picea glauca (Moench) Voss) through somatic embryogenesis (SE) has important applications in tree improvement programs and will help the forest industry to achieve maximum sustainable yield. The level of induction of embryogenic tissue and the yield of mature embryos through SE has reached acceptable levels using current protocols. However, a large percentage of these embryos produce abnormal seedlings. This problem needs to be assessed and this was done in the work described in this thesis. Empirically derived, uncontrolled partial desiccation procedures are currently used to improve germinaton. No systematic study has previously been done to correlate the effects of controlled desiccation on germinant quality. My study looked at the effects of controlled partial and complete desiccation of white spruce somatic embryos at four stages of development on subsequent germinant quality. Both slow desiccation at 5°C and flash desiccation at ambient temperature were examined. The effect of temperature treatments as an alternate means of improving germinant quality and its effect on desiccation tolerance were also examined. Dried somatic embryos are likely to suffer imbibitional damage as they (unlike zygotic embryos) have no protective structures surrounding them to regulate water uptake during imbibition. Therefore, the effects of various rehydration methods were also examined. Large numbers of mature embryos were required for our desiccation experiments. Therefore, a method of squashing the embryogenic tissue into a polypropylene mesh was developed. This method allowed embryogenic tissue to be easily transferred to fresh medium and produced a flat mat of mature embryos that were more accessible for harvesting. The tolerance of the embryos to desiccation, and the level of desiccation required to improve germinant quality, increased as the embryos matured. The largest improvement in germinant quality was achieved by slowly desiccating 39-d embryos at 5°C for 7 days over a 0.48 M NaCl solution with a water potential of -2 MPa and rehydrating them at 100% RH at a temperature of 5°C. This treatment produced approximately 84% normal germinants. More severe desiccation caused increasing damage. A temperature treatment of 5 and 10°C also improved germinant quality, producing 70- 80% normal germinants. The 5°C treatment can be used as a short-term storage method. Germinant quality from untreated embryos increased with maturity until the embryos became fully mature by 51 d, then quality quickly decreased. Mature 51-d embryos were stored for 8 weeks at 5°C with no loss of germinant quality. A 5°C temperature treatment for 4-8 weeks significantly improved the tolerance of 39-51 d embryos to flash desiccation (embryos were dried in a laminar flow hood and lost all free cytoplasmic water within 15 minutes). This has important applications in the development of synthetic seed. All of the 8-week cold stored 51-d embryos survived flash desiccation and 58% of them produced normal germinants. The roots developed desiccation tolerance faster than the cotyledons+hypocotyls. Rehydration experiments showed that slowly and rapidly desiccated embryos responded differently to the method of rehydration. Slowly desiccated embryos suffered less imbibitional damage if they were indirectly rehydrated at 100% RH. Flash desiccated embryos suffered less damage if they were rehydrated directly on germination medium. This suggests that there is no one simple explanation for damage as a result of desiccation and imbibition. Reduction of 2,3,5-triphenyltetrazolium chloride (TTC) was an effective test for delineating damaged areas in rehydrated embryos, but actual germination tests were the only way of accurately determining germinant quality. The above treatments have significantly improved germinant quality.
Interaction Between the Seed-Chalcid Wasp, Megastigmus spermotrophus and its Host, Douglas-fir (Pseudotsuga menziesii)
(2015-09-28) Donaleshen, Kathleen Louise; Aderkas, P. von; Ehlting, Jurgen
Megastigmus spermotrophus is a parasitic chalcid wasp that spends most of its life in the seed of its host, Douglas-fir (Pseudotsuga menziesii). The adult female wasp lays its eggs into the megagametophyte deep within the ovule; the larva prevents an unpollinated ovule from aborting, redirecting resources to feed itself. Host-site selection pressures that influence female oviposition depend on a number of factors. Morphological characteristics of Douglas-fir cones including seed size, seed location, and scale thickness were measured for every ovuliferous scale. Seeds infested by M. spermotrophus as well as seeds fused to galls intiated by a competing conophyte, Contarinia oregonensis were noted. Using a generalized linear mixed effects model, I found that seed position, and the presence of C. oregonensis, were strong predictors of Megastigmus infestation. The percent of M. spermotrophus infested seed was higher in the apical and basal regions of the cone where seeds were smaller, scales were thinner and C. oregonensis were less frequently found. M. spermotrophus was also found to exploit seeds in regions of the cone, where seeds rarely complete development. These data suggest that competitors may not be the only factor influencing infestation; factors of cone morphology are also important. Douglas-fir seed does not show any anatomically detectable defense response to Megastigmus attack. To study mechanisms of host manipulation and defense response of the seed I took a genomics approach. Four types of ovules/seeds were studied: 1. pollinated & uninfested, 2. pollinated & infested, 3. unpollinated & uninfested, and 4. unpollinated and infested. A de novo reference transcriptome was assembled. Transcripts were annotated based on sequence similarity to genes of Pinus taeda, Arabidopsis thaliana, Nasonia vitripennis, and the UniProt database. Expression values were estimated based on the alignment of the original reads back onto the reference transcriptome. Differentially expressed transcripts were identified. Oviposition of M. spermotrophus caused changes in expression of Douglas-fir transcripts. Functional classification of differentially expressed transcripts between infested and uninfested seed revealed genes with possible roles in wounding, but none specific to herbivory. Infested treatments had more transcripts similarly expressed to pollinated than unpollinated seeds suggesting that M. spermotrophus is capable of manipulating gene expression. These transcripts had functional roles related to seed storage, cell division and growth, solute transport, hormone signalling, and programmed cell death among others. Overall, this study reveals a select set of genes that may be involved in stress response to wounding and also genes important for seed development and maturation.
The Microbial Associates and Putative Venoms of Seed Chalcid Wasps (Hymenoptera: Torymidae: Megastigmus)
(2013-12-20) Paulson, Amber Rose; Perlman, Steven John; Aderkas, P. von
Conifer seed-infesting chalcids of the genus Megastigmus (Hymenoptera: Torymidae) are important forest pests. At least one species, M. spermotrophus Wachtl, has been shown to be able to manipulate the seed development of its host, Douglas-fir (Pseudotsuga menziesii) in remarkable ways, such as redirecting unfertilized ovules that would normally abort. The mechanism of host manipulation is currently unknown. Microbial associates and venoms are two potential mechanisms of host manipulation. Microbial associates are emerging as an important player in insect-plant interactions. There is also evidence that venoms may be important in gall-induction by phytophagous wasps. PCR and 16S rRNA pyrosequencing was used to characterize the microbial associates of Megastigmus and transcriptomic sequencing was used to identify putative venoms that were highly expressed in female M. spermotrophus. The common inherited bacterial symbionts Wolbachia and Rickettsia were found to be prevalent among several populations of Megastigmus spp. screened using a targeted PCR approach. A member of the Betaproteobacteria, Ralstonia, was identified as the dominant microbial associate of M. spermotrophus using 16S rRNA pyrosequencing. The transcriptome of M. spermotrophus was assembled de novo and three putative venoms were identified as highly expressed in females. One of these putative venoms, Aspartylglucosaminidase, (AGA) appears to have originated through gene duplication within the Hymenoptera and has been identified as a major venom component of two divergent parasitoid wasps. AGA was identified as a promising candidate for further investigation as a potential mechanism of early host manipulation by M. spermotrophus.
Population genomics of a timberline conifer, subalpine larch (Larix lyallii Parl.)
(2019-12-24) Vance, Marie; Aderkas, P. von; Hawkins, Barbara J.
Subalpine larch (Larix lyallii Parl.) has a narrow ecological niche at timberline in the Cascade Range and the Rocky Mountains of western North America. Demographic factors, including a long generation time (average 500 years) and a late arrival at sexual maturity (100-200 years), make it unlikely that this species will be able to adapt to predicted climate change. A better understanding of genetic structure and genetic diversity is necessary in order to effectively manage this species for future generations. Foliage from 62 populations of subalpine larch was collected in order to elucidate the range-wide population genomics of the species. DNA was extracted and a next-generation sequencing method, restriction site associated DNA sequencing (RAD-seq), was used to generate genome-wide single nucleotide polymorphism (SNP) marker data. Three genetically differentiated clusters were identified via principal components analysis, a discriminant analysis of principal components and Bayesian STRUCTURE analysis: the Cascade Range, the southern Rocky Mountains and the northern Rocky Mountains. A monophyletic group in the central Rocky Mountains was also identified in a dendrogram of genetic distance but this group had weak bootstrap support (49%), meaning genetic differentiation depends on relatively few genetic variants. Genetically differentiated groups should be prioritized for future management and conservation efforts. Negative values of Tajima’s D and preferred demographic scenarios generated by coalescent simulations indicated that 15 populations all have a recent history of expansion. Genetic diversity within these populations was found to be moderate (HO = 0.15 – 0.20), inbreeding coefficients were found to be high (FIS = 0.15 – 0.25) and genetic differentiation among populations was found to be high (average FST = 0.18). These results indicated that fragmentation driven by Holocene warming may have resulted in reduced effective population sizes. Smaller populations experience stronger genetic drift and an increased likelihood of inbreeding, which may hinder an adaptive response to natural selection. Still, parameter estimates for preferred demographic scenarios suggested a minimum effective population size of around 20,000 individuals, which is not considered small by most conservationists. A final study of 18 populations found local adaptation to cold temperature in the northern portion of the species range. In all seasons, populations from the northern Rocky Mountains had significantly higher cold tolerance than populations from the central Canadian Rocky Mountains and the northern Cascades. Winter cold tolerance showed strong clines associated with the frost-free period and degree days below zero. These two climate variables explained 65% of the explainable variance in phenotype when redundancy analysis models were conditioned on geography. Seven SNPs were identified that explained a significant portion of the variance in winter cold tolerance. Range-wide, additional SNPs were identified as FST outliers and/or as significantly correlated with environmental gradients, even after correcting for neutral genetic structure. Together, the results of this work indicate that dispersal, neutral evolutionary processes and natural selection have all played important roles in shaping patterns of genetic variation across the natural range of subalpine larch. All of these factors should be considered during the development of management and conservation strategies for this high-elevation conifer species.
Proteins in gymnosperm pollination drops.
(2014-12-18) Prior, Natalie Annastasia; Aderkas, P. von
Most gymnosperms produce a pollination drop that captures and transports pollen into the ovule. Pollination drops have other functions. These include influencing pollen germination and pollen tube growth, defending the ovule from pathogens and providing a food reward in insect-pollinated gymnosperms. Mineral and organic molecules, including proteins, are responsible for these additional functions. To date, pollination drops from a handful of conifers and one non-conifer gymnosperm, Welwitschia mirabilis, have been subjected to proteomic analysis. In the present study, tandem mass spectrometry was used to detect proteins in all gymnosperm lineages: cycads (Ceratozamia hildae, Cycas rumphii, Zamia furfuracea); Gnetales (Ephedra compacta, E. distachya, E. foeminea, E. likiangensis, E. minuta, E. monosperma, E. trifurca; Gnetum gnemon; Welwitschia mirabilis); Ginkgo biloba; conifers (Taxus x media). PEAKS 6 DB (Bioinformatics Solutions, Waterloo, ON, Canada) was used to make protein identifications. Proteins were detected in all gymnosperm species analyzed. The numbers of proteins identified varied between samples as follows: one protein in Welwitschia female; nine proteins in Cycas rumphii; 13 proteins on average in Ephedra spp.; 17 proteins in Gnetum gnemon; 38 proteins on average in Zamia furfuracea; 57 proteins in Ginkgo biloba; 61 proteins in Ceratozamia hildae; 63 in Taxus x media; 138 proteins in Welwitschia male. The types of proteins identified varied widely. Proteins involved in carbohydrate modification, e.g. galactosidase, chitinase, glycosyl hydrolase, glucosidase, were present in most gymnosperms. Similarly, defence proteins, e.g. reduction-oxidation proteins, lipid-transfer proteins and thaumatin-like proteins, were identified in many gymnosperms. Gymnosperms that develop a deep pollen chamber as the nucellus degrades, e.g., cycads, Ginkgo, Ephedra, generally contained higher proportions of proteins localized to intracellular spaces. These proteins represent the pollination drop degradome. Gymnosperms that either lack a pollen chamber, e.g. Taxus, or have a shallow pollen chamber, e.g. Gnetum, had greater proportions of extracellular proteins. These proteins represent the pollination drop secretome. Our proteomic analyses support the hypothesis that the pollination drops of all extant gymnosperms constitute complex reproductive secretions.
Proteins in the ovular secretions of conifers
(2008-04-10T05:58:02Z) O'Leary, Stephen James Bernard; Aderkas, P. von
Most conifers employ a liquid secretion originating fiom within the ovule at some point during reproduction. Although widely known, these ovular secretions have been poorly characterized. Biochemical analyses of these liquids have been limited to reports of sugars, amino acids, organic acids, and calcium. The purpose of this study was to investigate the physiological regulation of conifer ovular secretions and to further elucidate their contents. Postpollination droplet production was measured in three hybrid larch trees (Larix x marschlinsii Coaz) in relation to xylem water tension in the stem. Secretion production was not correlated to the predictable diurnal fluctuation of tree water status. The ovular secretions of this species were found to be independent of the physiological condition of the stem and are likely under the control of local structures such as the cones or ovules. The concentrations of glucose, fi-uctose, and sucrose were measured in the secretions of larch and hybrid yew (Taxus x media Rehder). In agreement with results &om other conifers, the concentrations of glucose (156 mM) and fructose (145 mM) in the larch secretion were found to be higher than sucrose (1 08 mM). The pollination droplet of yew displayed a novel pattern. The sucrose concentration in this species (23 mM) was found to be an order of magnitude higher than either glucose (2.7 mM) or hctose (2.1 mM). The ovular secretions of larch, yew, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and western red cedar (Thuja plicata Donn. ex D. Donn) were found to contain complex mixtures of proteins when examined by polyacrylamide gel electrophoresis or reversed phase high performance liquid chromatography. The proteins of larch and yew were produced consistently from tree to tree and throughout the period of secretion production. N-terminal amino acid sequencing and antibody recognition identified proteins in larch and yew samples believed to be involved in pollen germination and the promotion of pollen tube elongation. The cell wall modifLing enzyme xyloglucan endotransglycosylase (XET) was identified in the larch secretion. Immunolocalization identified cells in the apical region of the larch micropyle as the site of XET production. Arabinogalactan proteins (AGPs), known to promote pollen tube growth in angiosperms, were found in the secretions of both conifer species. AGP production in the yew ovule was localized to the nucellus. Four pathogenesis-related (PR) proteins were identified in the larch and yew ovular secretions. A lipid transfer protein (LTP) belonging to the PR-14 group was identified in the larch secretion by N-terminal amino acid sequencing. A thaumatin-like protein (TLP, PR-5) was tentatively identified in the larch sample by antibody recognition. One acidic and one basic TLP were identified in the yew secretion by tandem mass spectrometry (MSMS) sequencing of internal peptide fragments. These proteins were named TmTLPa and TxmTLPb respectively. MSMS sequencing also identified a P-1,3-glucanase of the PR-2 group in the yew secretion (TmpGlu). The cDNA coding for TxmTLPa was sequenced and assessed for heterologous protein expression. The nucleic acid sequence predicts a preprotein of 233 amino acid residues with a 28 residue export signal. The putative mature protein has a predicted molecular weight of 21.40 kDa and pI of 4.4. The deduced protein sequence contains 16 cysteine residues conserved across TLPs, and five residues that contribute to the acidic cleft of antifbngal TLPs. In order to produce Z'xmTLPa in sufficient quantities to perform bioassays, the mature sequence of this protein has been inserted into a plasmid vector for the expression of a TxmTLPa fusion protein. This report contains the first simultaneous study of ovular secretion production and tree water status, the first measurements of the sugar concentrations in the ovular liquids of L. x marschlinsii and T. x media, and the first identification of proteins in the ovular secretion of any seed plant.
The queen root of this clime : ethnoecological investigations of blue camas (Camassia leichtlinii (Baker) Wats., C. quamash (Pursh) Greene ; Liliaceae) and its landscapes on southern Vancouver Island, British Columbia
(2008-04-10T06:01:27Z) Beckwith, Brenda Raye; Turner, Nancy J.; Aderkas, P. von
Bulbs of camas (Camassia leichtlinii and C. quamash; Liliacaeae) were an important native root vegetable in the economies of Straits Salish peoples. Intensive management not only maintained the ecological productivity of &us valued resource but shaped the oak-camas parklands of southern Vancouver Island. Based on these concepts, I tested two hypotheses: Straits Salish management activities maintained sustainable yields of camas bulbs, and their interactions with this root resource created an extensive cultural landscape. I integrated contextual information on the social and environmental histories of the pre- and post-European contact landscape, qualitative records that reviewed Indigenous camas use and management, and quantitative data focused on applied ecological experiments. I described how the cultural landscape of southern Vancouver Island changed over time, especially since European colonization of southern Vancouver Island. Prior to European contact, extended families of local Straits Salish peoples had a complex system of root food production; inherited camas harvesting grounds were maintained within this region. Indigenous peoples adapted their economic decisions and traditional food needs to fit shifting social and environmental parameters. Through ecological experimentation I examined the growth and development of camas in nursery cold fiames and in simulated Indigenous management techtuques of naturally occurring camas populations. These two studies showed that camas demonstrated a variety of growth patterns and maintained a range of developmental phases, leading me to conclude that this genus is a good candidate for regular management. The field study also confirmed a high degree of habitat heterogeneity characteristic of this region. I developed a multiscalar model of integrated Indigenous root management and reconstructed the ethnoecological dynamics of former camas landscapes. From this I derived management recommendations for future camas landscapes. I elucidated how camas harvest grounds were essentially agroecosystems, maintained by a range of anthropogenic disturbance patterns. The evolution of camas cultivation was a continuum of intensifjring intervention between humans and a native root crop, a relationship of human-environment interaction that quickly ended, for the most part, soon after European contact. Successful restoration of today's degraded camas populations, and of the nationally endangered Garry oak ecosystems, in which Camassia is a major herbaceous component, is dependent on ethnoecologically integrated restoration initiatives based on multidisciplinary landscape reconstruction studies.
Reprogramming the expression of the double-stranded RNA mitovirus OnuMV1c from the mitochondria to the cytoplasm in the fungal pathogen Ophiostoma novo-ulmi
(2015-08-26) Dort, Erika; Hintz, William E. A.; Aderkas, P. von
Dutch elm disease (DED) is a debilitating wilt disease that has decimated elm populations globally. The current pandemic of this disease is caused by the ascomycete fungal pathogen Ophiostoma novo-ulmi. A number of strategies have been used to attempt to mitigate the effects of DED but none have met any sustainable success, and the disease continues to have severe ecological and economic impacts. Consequently, research focus has turned to the development of control strategies at the genetic level. One such genetic strategy is the use of naturally occurring fungal viruses (mycoviruses) to induce hypovirulence in their fungal hosts. Hypovirulence, or attenuation of fungal pathogenicity using mycoviruses, has been well studied in other systems but has yet to be developed for O. novo-ulmi. A candidate virus, OnuMV1c, was found in an isolate of O. novo-ulmi (93-1224) at the western Canadian disease front and its genome was sequenced. OnuMV1c is a mitochondrial virus and has a 3.1 kb single-stranded positive RNA genome that encodes an RNA-dependent RNA polymerase (RdRp) involved in its replication as a double-stranded RNA molecule. It exists in O. novo-ulmi mitochondria in both its single-stranded and double-stranded forms. Our research group identified OnuMV1c as a potential candidate for biological control of Dutch elm disease. Our long-term research goal is to use the virus as a means to activate the RNA interference pathway of O. novo-ulmi, leading to down-regulation of genes involved in pathogenicity. If OnuMV1c is engineered such that it carries an RNA interference cassette in addition to its own complement of genes, it could act as an enhanced hypovirus. RNA interference (RNAi) is a cytoplasmic process, and therefore in order to use OnuMV1c for RNAi the viral genome needed to be reprogrammed such that it could be expressed in the cytoplasm rather than the mitochondria. The objectives of my master’s research were to 1) genetically engineer OnuMV1c to express in the cytoplasm using a cDNA reverse genetics approach, and 2) test the functionality of the re-engineered cDNA OnuMV1c virus (MV1cCyt). The first objective was accomplished by modifying codons in the RdRp sequence of OnuMV1c such that the sequence could be translated in the cytoplasm. This genetically engineered cytoplasmic version of OnuMV1c, named MV1cCyt, was flanked with exogenous promoter and terminator sequences to drive its transcription. The entire construct was engineered as a cDNA molecule and was cloned into the fungal transformation vector pAN7-1, which was used to transform O. novo-ulmi protoplasts. The second objective was achieved through the use of strand-specific RT-PCR, a technique that allowed the detection of both the positive and negative strands of MV1cCyt. Results indicated that while four individual cell lineages contained MV1cCyt cDNA stably integrated into the nuclear genome, only one transformant was able to produce double-stranded MV1cCyt RNA. These results have important implications for the use of OnuMV1c as an engineered hypovirus and represent the first step towards the development of a biological control strategy for Dutch elm disease.
The role of prezygotic events in the reproductive success of conifers
(2018-09-14) Rise, Marlies; Aderkas, P. von
The purpose of this study was to determine if any prezygotic breeding barriers exist in conifers. Prezygotic events were analyzed for both in vivo and in vitro systems in conifers. The events that were monitored included archegonial development, pollen germination, pollen tube growth and penetration of female structures and gamete delivery. Aspects of archegonial development in vivo were verified by serial sections of glycol methacrylate embedded sections. This study describes novel abnormal archegonial structures in Dunkeld larch. Normal archegonial development was also investigated in Dunkeld larch and Douglas-fir. This study demonstrates that the ratio between egg nuclear volume and egg cell volume in conifers is consistent with the linear relationship that is known to exist between cell and nuclear volume in all other land plants. In contrast to other plant cell nuclei, most of the DNA in the egg cell nuclei of conifers is localized at the periphery of these organelles. In addition, the relationship between DNA content and nuclear volume in conifer egg cells is not consistent with the linear relationship that is shown between nuclear DNA content and nuclear volume in angiosperms. This study also examined the interactions between pollen and ovules as well as interaction of pollen and female gametophytes in vivo to determine if there were any prezygotic barriers to foreign pollen in conifers. Dissections of Dunkeld larch and Douglas-fir ovules that had been pollinated with either Dunkald larch, Douglas-fir, western white pine or Interior spruce pollens revealed that heterospecific pollen has a reduced capacity to germinate in these ovules. Serial sections of glycol methacrylate embedded specimens showed that the nucellus also posed a barrier to some foreign pollen. Western white pine pollen was unable to penetrate the nucellus of either larch or Dougals fir. However, Douglas-fir pollen was able to penetrate not only the nucellus of larch ovules, but also megagametophytes and egg cells into which it delivered gametes. Larch pollen was also observed to penetrate Douglas-fir nucelluses and megagametophytes, though no gamete delivery was observed. In vitro co-culture was also used to study the interaction of pollen and megagametophytes of different genera. Cells of megagametophytes provided no barrier to pollen tubes, and pollen tubes were able to penetrate any part of megagametophytes. Delivery of gametes was confirmed between spruce and larch. This study demonstrated that the megagametopbyte plays no role in male selection. To study the effects of culturing on megagametophytes of Douglas-fir and larch, cones were collected at the time of fertilization and the megagametophytes were removed and then placed on medium. A variety of cell types proliferated including prothallial, neck and jacket cells. Some of these multiplying cells showed a binucleate condition. This was the first report of neck cell multiplication and induction of a binucleate state for gymnosperm megagametophyte cells in vitro. This study demonstrates that a number of prezygotic events can influence reproductive success in conifers.
Safe sex in Douglas-fir
(2008-04-10T05:58:01Z) Poulis, Brett Allan Douglas; Aderkas, P. von
Somatic cell genetics in larches (Larix spp.)
(2017-05-18) Pattanavibool nee Vongvijitra, Rungnapar; Aderkas, P. von
Studies of somatic cell genetics in larches (Larix spp.) were carried out using somatic hybridization, cytogenetics as well as fluorescence in situ hybridization. Haploid embryogenic protoplasts are ideal sources for somatic hybridization if they possess stable chromosome complements. In my protoplast fusion experiments, I used diploid embryogenic protoplasts because genetic variation was detected in the haploid lines available. Cytogenetics coupled with fluorescence in situ hybridization was used to reveal genetic instabilities in haploid embryogenic lines as well as to produce a standard karyotype of Larix decidua. A diploid embryogenic culture of tamarack (Larix laricina, line L2) was used as one of the fusion partners while the other partner used was one of the two hybrid larches (Larix x leptoeuropaea, line L5 and Larix x eurolepis, line L6 ). The selection system was based on complementation of metabolic inhibition (with sodium iodoacetate) of tamarack and the lack of ability to produce mature embryos of the hybrid larches. Ideally, only the heterofused cells would have been able to regenerate. The vital fluorescent dyes, DiOC₆ and R6 , were used to stain protoplasts of each parent to determine fusion events and frequencies. I compared fusion firequency as well as cell division between fusion mediated by PEG or electric pulses. PEG-mediated fusion resulted in 14-18 % of heterofused cells. All electrofusion treatments gave much lower fusion frequencies, at only 4-8 %. Although the percentages of cell division after 4d of PEG-fusion (17-24%) and electrofusion (19.3%) were about the same, PEG-fusion was found to be a more efficient means than electrofusion. Sodium iodoacetate at a concentration of 4-5 mM was found to efficiently inactivate the protoplasts of tamarack. All control-treated protoplasts as well as mixed cultures (unfused protoplasts) died. Tamarack protoplasts produced mature single embryos, whereas protoplasts of hybrid larches never completed embryogenesis. Some post-fusion products produced colonies and mature embryos. RAPD was used to verify the hybridity of those fusion-derived colonies and mature embryos. Of thirty-one fusion experiments between lines L2 and L5, only one produced individual colonies. Of the thirteen colonies which developed in that experiment, none yielded mature embryos. RAPD analysis of the colonies picked out from L2/L5 fusion showed DNA banding characteristics of L5. From twenty four experiments fusing L2 and L6 , there were five experiments which produced colonies. A total of two hundred and thirty nine individual colonies and nineteen single mature embryos were picked out from those L2/L6 fusions. RAPD banding profiles of eighty seven colonies and nineteen mature embryos showed DNA banding characteristics of L2 only. Tested haploid embryogenic lines (total of 6 lines; n=12) of Larix decidua initiated from megagametophyte tissue were maintained on half-strength Litvay’s medium without growth regulators. All lines had been verified as being haploid by chromosome squashes when they were initiated. Some lines have been stably haploid for only a short period of time while others have been stable for many years. Variations in chromosome numbers increased proportionately with the age of the culture. Haploids doubled their chromosome numbers. Aneuploidization occurred because of unequal separation of the chromosomes. Unusual events during mitosis such as formation of anaphase bridges, fragmentation of chromosomes, and development of long kinetochores were detected. There was a tendency of rising chromosome numbers in all lines tested over the years. Fluorescence in situ hybridization (FISH) was used to physically map highly repetitive sequences of genes coding for 18S-5.8S-26S rDNA on Larix decidua chromosomes. A karyotype of L. decidua (2n=24) was created from average relative lengths derived from the six best squashes with strong probe-target FISH signals. Hybridization of 18S-26S rDNA onto L. decidua chromosomes gave very precise locations of secondary constriction as well as unexpressed nucleolar organizer regions. In L. decidua, there were 6 major 18S-26S rDNA loci detected in 60.53% of cells (23 out of 39 cells). Five I8S-26S rDNA loci were also found but at a lower rate of 39.47%. All loci were expressed and located at the sites of secondary constriction on chromosomes 2, 4 and 7. Two extra locations of 18S-26S rDNA were mapped on aneuploid chromosomes (30 chromosomes) derived from cells of an aneuploid line (line 2110) of L. decidua. Chromosome measurement resulted in a preliminary karyotype of this line. The relative total lengths and locations of I8S-26S rDNA of standard (2n=24) chromosomes and aneuploid (2n=30) chromosomes was compared.
Somatic embryo development and phenotypic variation in an abscisic acid-independent line of Larix x eurolepis
(2018-08-02) Hay, Elizabeth Irene; Aderkas, P. von
The objectives of this thesis were to trace the developmental pathways of somatic embryos of an abscisic-acid independent line of Larix x eurolepis. to catalogue the phenotypes of mature embryos, to determine critical stages of development and to attempt to increase the number of maturing somatic embryos. The low rate of maturation could not be entirely explained by differences in phenotypes of early embryos, critical stages of development, or the lack of plant growth regulators in the medium. In addition, the shape and epidermal type of the mature embryo did not always determine the type of epicotyl produced, nor did it affect the rooting and mortality rates. Six types of embryonal structures were evident in the aggregates of line 2086: (1) a smooth (SEMLS) or (2) rough (REMLS) embryonal mass subtended by a cylindrical, compact, long suspensor. (3) a rough embryonal mass subtended by a long, loose suspensor (REMLLS). (4) a rough embryonal mass subtended by a suspensor arising from greater than one quarter of the surface area of the embryonal mass (REMST). (5) a rough embryonal mass subtended by a short, compact, cylindrical suspensor (REMSS). and (6) a cluster of meristematic cells which may or may not have single suspensor cells attached (MC). For isolated embryonal structures of all types, to continue development into a nodule or a mature embryo was the least common fate, while proliferation and developmental arrest were more common. In general, the more organized embryonal structure types (SEMLS and REMLS) had higher rates of maturation compared to the other 4 types but the most common fate was still developmental arrest (74% SEMLS. 62% REMLS), followed by proliferation (10% SEMLS. 30% REMLS), and nodule or embryo development (16% SEMLS. 9% REMLS). REMLLS and REMST embryonal structures became developmentally arrested or proliferated (43-47%) while the rate of nodules/mature embryos production was 9-11%. Neither individual REMSS nor MC structures produced any nodules or mature embryos, but REMSS had a lower rate of developmental arrest (81%) and a higher rate of proliferation (19%) than MC (89% and 11% respectively). Embryos at more advanced stages of development were less likely to die, become developmentally arrested or become nodules, but more likely to become mature embryos than embryos at less advanced stages of development. A critical stage of development appeared to be the focal zone stage at the formation of a complete polyphenol band around the basal end of the embryonal mass. At this stage, the majority of immature embryos became mature embryos (61%) while only 3% of the embryos died. 10% became developmentally arrested, and 20% became nodules. The majority of mature somatic embryos were normally proportioned with a smooth epidermis (43%) rather than vitrified (12%). normal with a rough epidermis (12%) or misshapen (smooth or rough. 33%). The shape of the mature embryo was associated with the type of epidermis, with mature somatic embryos with normal proportions more likely to have smooth epidermis (78%) than a rough epidermis (22%) while mature embryos with abnormal proportions were as likely to have a smooth epidermis as a rough epidermis. The shape of the mature embryo was associated with the shape of the epicotyl produced. Normal-smooth, mature embryos were more likely to produce normal-smooth epicotyls (73%) than twin epicotyls (21%), vitrified epicotyls (2%) or misshapen epicotyls (5%) compared to vitrified mature embryos (42% normal-smooth epicotyls, 34% twin epicotyls, 23% vitrified epicotyls, 1% misshapen epicotyls) or misshapen mature embryos (22% normal-smooth epicotyls, 47% twin epicotyls, 7% vitrified epicotyls, 24% misshapen smooth/rough embryos). The number of mature embryos which germinated or died was not associated with either the epidermal quality or the shape of the mature embryo. Few SEMLS or REMLS embryonal structures responded to auxin and cytokinin treatments. There appeared to be a trend towards less developmental arrest and proliferation and more nodules/mature embryos produced on media with no auxin compared to media with 2,4-D and a trend towards more developmental arrest and fewer nodules/mature embryos on media without BA compared to media with BA. Only nodules on media without plant growth regulators produced roots or cotyledons. There was no effect of embryonal structure type (SEMLS or REMLS), or sucrose concentration (58 μM or 174 μM) on the maturation of immature embryos, but on media without ABA, fewer immature embryos proliferated or became developmently arrested and more embryos became nodules or mature embryos than on medium with 6-24 μM ABA.
Transcriptomic analysis of Douglas-fir megagametophyte development and abortion
(2013-08-30) Boyes, Ian; Aderkas, P. von; Ehlting, Jurgen
Douglas-fir develops a megagametophyte regardless of the pollination state of the ovule, whereas many other conifers develop a megagametophye in response to polli- nation. Megagametophytes in unfertilized ovules degrade two weeks following fertil- ization of the surrounding population. This is mediated by programmed cell death (PCD). Pollinated and unpollinated megagametophytes were dissected from Douglas- fir cones and extracted for RNA, which was then used as input for sequencing. A transcriptome was assembled from this data and expression levels were calculated. The data were fitted to quadratic regressions to produce coexpression groups. There is no clear upregulation of PCD effectors in the unpollinated megagametophyte. Po- tential regulators of megagametophyte fate are present in the data. Some are as- sociated with ABA signalling and proanthocyanadin biosynthesis while others share similarity to known regulators of PCD. Seed development processes are represented in the expression data, which support current knowledge of conifer seed development and provide targets for research.
Variation in reproductive characteristics of lodgepole pine (Pinus contorta var. latifolia) in British Columbia
(2014-01-09) Berland, Anne; Aderkas, P. von; Anholt, Bradley Ralph
Lodgepole pine (Pinus contorta var. latifolia) is the most wide-ranging pine in North America. Populations in British Columbia vary widely in phenotypic and genotypic characteristics. The effect of climate on variation in reproductive characteristics has never been examined, yet is vital to the production of seed necessary for reforestation. This study aims to determine the relationship between the climate in B.C and variation in female cone and seed characteristics. The study makes use of the Illingworth provenance trial, sixty common garden plots that are distributed throughout British Columbia. Female cones from six provenances were collected at 21 sites during the summer of 2012. The number of scales was counted and maximum length was measured for each cone. Seed was extracted and counted. Variables were pooled for each tree. The climate at each site was described using data from ClimateWNA. Principal components analysis was used to reduce the highly correlated data set to the first two principal components (PC1 and PC2), which together described 76.7% of the variation in the data. PC1 was most closely aligned with variables related to temperature, the number of frost-free days, and degree-days above 5°C or below 0°C. PC2 was most closely aligned with precipitation and moisture variables. The reproductive variables were moderately positively correlated with one another. Analysis of variance indicated that average cone length and the average number of seeds per cone were significantly affected by both site and provenance, however the average number of seeds per cone was not. Average values of each reproductive trait for each site were modelled against the first two principal components using multiple analysis of variance and univariate linear modelling. The best-fit model for the average number of scales per cone included PC1 and PC2, however the model only described 4.9% of the variation in the data. The best-fit model for the number of seeds included only PC1, and iv the model only explained 4.1% of the variation in the data. The model for average cone length had the strongest results, with a model that included PC2 and explained 18.7% of the data. The results of the study indicate that climate is not the most important factor in predicting reproductive characteristics such as cone length, and the number of scales and seed per cone. The significant effect of moisture on average cone length was the strongest relationship identified in the study. The reproductive traits were best described by their stability across the climates of the test sites. High genetic variation in lodgepole pine populations may be contributing to the stability of reproductive traits. Lodgepole pine female cone and seed traits were stable for mature trees over a wide range of provenances and climate regions.

Browsing by Supervisor "Aderkas, P. von"

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