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Stejskal J, Čepl J, Neuwirthová E, Akinyemi OO, Chuchlík J, Provazník D, Keinänen M, Campbell P, Albrechtová J, Lstibůrek M, Lhotáková Z. Making the Genotypic Variation Visible: Hyperspectral Phenotyping in Scots Pine Seedlings. PLANT PHENOMICS (WASHINGTON, D.C.) 2023; 5:0111. [PMID: 38026471 PMCID: PMC10644830 DOI: 10.34133/plantphenomics.0111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 10/10/2023] [Indexed: 12/01/2023]
Abstract
Hyperspectral reflectance contains valuable information about leaf functional traits, which can indicate a plant's physiological status. Therefore, using hyperspectral reflectance for high-throughput phenotyping of foliar traits could be a powerful tool for tree breeders and nursery practitioners to distinguish and select seedlings with desired adaptation potential to local environments. We evaluated the use of 2 nondestructive methods (i.e., leaf and proximal/canopy) measuring hyperspectral reflectance in the 350- to 2,500-nm range for phenotyping on 1,788 individual Scots pine seedlings belonging to lowland and upland ecotypes of 3 different local populations from the Czech Republic. Leaf-level measurements were collected using a spectroradiometer and a contact probe with an internal light source to measure the biconical reflectance factor of a sample of needles placed on a black background in the contact probe field of view. The proximal canopy measurements were collected under natural solar light, using the same spectroradiometer with fiber optical cable to collect data on individual seedlings' hemispherical conical reflectance factor. The latter method was highly susceptible to changes in incoming radiation. Both spectral datasets showed statistically significant differences among Scots pine populations in the whole spectral range. Moreover, using random forest and support vector machine learning algorithms, the proximal data obtained from the top of the seedlings offered up to 83% accuracy in predicting 3 different Scots pine populations. We conclude that both approaches are viable for hyperspectral phenotyping to disentangle the phenotypic and the underlying genetic variation within Scots pine seedlings.
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Affiliation(s)
- Jan Stejskal
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences,
Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Jaroslav Čepl
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences,
Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Eva Neuwirthová
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences,
Czech University of Life Sciences Prague, Prague, Czech Republic
- Department of Experimental Plant Biology,
Charles University, Prague, Czech Republic
| | - Olusegun Olaitan Akinyemi
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences,
Czech University of Life Sciences Prague, Prague, Czech Republic
- Department of Environmental and Biological Sciences,
University of Eastern Finland, Joensuu, Finland
| | - Jiří Chuchlík
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences,
Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Daniel Provazník
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences,
Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Markku Keinänen
- Department of Environmental and Biological Sciences,
University of Eastern Finland, Joensuu, Finland
- Center for Photonic Sciences,
University of Eastern Finland, Joensuu, Finland
| | - Petya Campbell
- Department of Geography and Environmental Sciences,
University of Maryland Baltimore County, Baltimore, MD, USA
- Biospheric Sciences Laboratory,
NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Jana Albrechtová
- Department of Experimental Plant Biology,
Charles University, Prague, Czech Republic
| | - Milan Lstibůrek
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences,
Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Zuzana Lhotáková
- Department of Experimental Plant Biology,
Charles University, Prague, Czech Republic
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Shang H, Field DL, Paun O, Rendón-Anaya M, Hess J, Vogl C, Liu J, Ingvarsson PK, Lexer C, Leroy T. Drivers of genomic landscapes of differentiation across a Populus divergence gradient. Mol Ecol 2023; 32:4348-4361. [PMID: 37271855 DOI: 10.1111/mec.17034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/20/2023] [Accepted: 05/23/2023] [Indexed: 06/06/2023]
Abstract
Speciation, the continuous process by which new species form, is often investigated by looking at the variation of nucleotide diversity and differentiation across the genome (hereafter genomic landscapes). A key challenge lies in how to determine the main evolutionary forces at play shaping these patterns. One promising strategy, albeit little used to date, is to comparatively investigate these genomic landscapes as progression through time by using a series of species pairs along a divergence gradient. Here, we resequenced 201 whole-genomes from eight closely related Populus species, with pairs of species at different stages along the divergence gradient to learn more about speciation processes. Using population structure and ancestry analyses, we document extensive introgression between some species pairs, especially those with parapatric distributions. We further investigate genomic landscapes, focusing on within-species (i.e. nucleotide diversity and recombination rate) and among-species (i.e. relative and absolute divergence) summary statistics of diversity and divergence. We observe relatively conserved patterns of genomic divergence across species pairs. Independent of the stage across the divergence gradient, we find support for signatures of linked selection (i.e. the interaction between natural selection and genetic linkage) in shaping these genomic landscapes, along with gene flow and standing genetic variation. We highlight the importance of investigating genomic patterns on multiple species across a divergence gradient and discuss prospects to better understand the evolutionary forces shaping the genomic landscapes of diversity and differentiation.
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Affiliation(s)
- Huiying Shang
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vienna, Austria
- Xi'an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, Xi'an, China
| | - David L Field
- School of Science, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Ovidiu Paun
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Martha Rendón-Anaya
- Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Jaqueline Hess
- Helmholtz Centre for Environmental Research, Halle (Saale), Germany
| | - Claus Vogl
- Department of Biomedical Sciences, Vetmeduni Vienna, Vienna, Austria
| | - Jianquan Liu
- Key Laboratory for Bio-resources and Eco-environment, College of Life Science, Sichuan University, Chengdu, China
| | - Pär K Ingvarsson
- Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Christian Lexer
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Thibault Leroy
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
- GenPhySE, INRAE, INP, ENVT, Université de Toulouse, Castanet-Tolosan, France
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Seeley MM, Stacy EA, Martin RE, Asner GP. Foliar functional and genetic variation in a keystone Hawaiian tree species estimated through spectroscopy. Oecologia 2023; 202:15-28. [PMID: 37171625 DOI: 10.1007/s00442-023-05374-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 04/11/2023] [Indexed: 05/13/2023]
Abstract
Imaging spectroscopy has the potential to map closely related plant taxa at landscape scales. Although spectral investigations at the leaf and canopy levels have revealed relationships between phylogeny and reflectance, understanding how spectra differ across, and are inherited from, genotypes of a single species has received less attention. We used a common-garden population of four varieties of the keystone canopy tree, Metrosideros polymorpha, from Hawaii Island and four F1-hybrid genotypes derived from controlled crosses to determine if reflectance spectra discriminate sympatric, conspecific varieties of this species and their hybrids. With a single exception, pairwise comparisons of leaf reflectance patterns successfully distinguished varieties of M. polymorpha on Hawaii Island as well as populations of the same variety from different islands. Further, spectral variability within a single variety from Hawaii Island and the older island of Oahu was greater than that observed among the four varieties on Hawaii Island. F1 hybrids most frequently displayed leaf spectral patterns intermediate to those of their parent taxa. Spectral reflectance patterns distinguished each of two of the hybrid genotypes from one of their parent varieties, indicating that classifying hybrids may be possible, particularly if sample sizes are increased. This work quantifies a baseline in spectral variability for an endemic Hawaiian tree species and advances the use of imaging spectroscopy in biodiversity studies at the genetic level.
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Affiliation(s)
- M M Seeley
- Center for Global Discovery and Conservation Science, Arizona State University, Hilo, HI, 96720, USA.
- School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ, 85281, USA.
| | - E A Stacy
- School of Life Sciences, University of Nevada, Las Vegas, NV, 89154, USA
| | - R E Martin
- Center for Global Discovery and Conservation Science, Arizona State University, Hilo, HI, 96720, USA
- School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ, 85281, USA
| | - G P Asner
- Center for Global Discovery and Conservation Science, Arizona State University, Hilo, HI, 96720, USA
- School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ, 85281, USA
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Stasinski L, White DM, Nelson PR, Ree RH, Meireles JE. Reading light: leaf spectra capture fine-scale diversity of closely related, hybridizing arctic shrubs. THE NEW PHYTOLOGIST 2021; 232:2283-2294. [PMID: 34510452 PMCID: PMC9297881 DOI: 10.1111/nph.17731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/06/2021] [Indexed: 05/26/2023]
Abstract
Leaf reflectance spectroscopy is emerging as an effective tool for assessing plant diversity and function. However, the ability of leaf spectra to detect fine-scale plant evolutionary diversity in complicated biological scenarios is not well understood. We test if reflectance spectra (400-2400 nm) can distinguish species and detect fine-scale population structure and phylogenetic divergence - estimated from genomic data - in two co-occurring, hybridizing, ecotypically differentiated species of Dryas. We also analyze the correlation among taxonomically diagnostic leaf traits to understand the challenges hybrids pose to classification models based on leaf spectra. Classification models based on leaf spectra identified two species of Dryas with 99.7% overall accuracy and genetic populations with 98.9% overall accuracy. All regions of the spectrum carried significant phylogenetic signal. Hybrids were classified with an average overall accuracy of 80%, and our morphological analysis revealed weak trait correlations within hybrids compared to parent species. Reflectance spectra captured genetic variation and accurately distinguished fine-scale population structure and hybrids of morphologically similar, closely related species growing in their home environment. Our findings suggest that fine-scale evolutionary diversity is captured by reflectance spectra and should be considered as spectrally-based biodiversity assessments become more prevalent.
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Affiliation(s)
- Lance Stasinski
- School of Biology and EcologyUniversity of MaineOronoME04469USA
| | - Dawson M. White
- Department of Science and EducationField MuseumChicagoIL60605USA
| | - Peter R. Nelson
- Schoodic InstituteWinter HarborME04693USA
- School of Forest ResourcesUniversity of MaineOronoME04469USA
| | - Richard H. Ree
- Department of Science and EducationField MuseumChicagoIL60605USA
| | - José Eduardo Meireles
- School of Biology and EcologyUniversity of MaineOronoME04469USA
- Maine Center for Genetics in the EnvironmentUniversity of MaineOronoME04469USA
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Zhou J, Zhang S, Wang J, Shen H, Ai B, Gao W, Zhang C, Fei Q, Yuan D, Wu Z, Tembrock LR, Li S, Gu C, Liao X. Chloroplast genomes in Populus (Salicaceae): comparisons from an intensively sampled genus reveal dynamic patterns of evolution. Sci Rep 2021; 11:9471. [PMID: 33947883 PMCID: PMC8096831 DOI: 10.1038/s41598-021-88160-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/06/2021] [Indexed: 02/02/2023] Open
Abstract
The chloroplast is one of two organelles containing a separate genome that codes for essential and distinct cellular functions such as photosynthesis. Given the importance of chloroplasts in plant metabolism, the genomic architecture and gene content have been strongly conserved through long periods of time and as such are useful molecular tools for evolutionary inferences. At present, complete chloroplast genomes from over 4000 species have been deposited into publicly accessible databases. Despite the large number of complete chloroplast genomes, comprehensive analyses regarding genome architecture and gene content have not been conducted for many lineages with complete species sampling. In this study, we employed the genus Populus to assess how more comprehensively sampled chloroplast genome analyses can be used in understanding chloroplast evolution in a broadly studied lineage of angiosperms. We conducted comparative analyses across Populus in order to elucidate variation in key genome features such as genome size, gene number, gene content, repeat type and number, SSR (Simple Sequence Repeat) abundance, and boundary positioning between the four main units of the genome. We found that some genome annotations were variable across the genus owing in part from errors in assembly or data checking and from this provided corrected annotations. We also employed complete chloroplast genomes for phylogenetic analyses including the dating of divergence times throughout the genus. Lastly, we utilized re-sequencing data to describe the variations of pan-chloroplast genomes at the population level for P. euphratica. The analyses used in this paper provide a blueprint for the types of analyses that can be conducted with publicly available chloroplast genomes as well as methods for building upon existing datasets to improve evolutionary inference.
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Affiliation(s)
- Jiawei Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Shuo Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Jie Wang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
- School of Landscape and Architecture, Zhejiang Provincial Key Laboratory of Germplasm Innovation and Utilization for Garden Plants, Key Laboratory of National Forestry and Grassland Administration on Germplasm Innovation and Utilization for Southern Garden Plants, Zhejiang A & F University, Hangzhou, 311300, China
| | - Hongmei Shen
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
- The Second Peoples's Hospital of Nantong, Nantong, 226000, Jiangsu, China
| | - Bin Ai
- Foshan Green Development Innovation Research Institute, Foshan, 528000, Guangdong, China
| | - Wei Gao
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Cuijun Zhang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Qili Fei
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Daojun Yuan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Zhiqiang Wu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
- The College of Horticulture, Shanxi Agricultural University, Taigu, 030801, Shanxi, China
| | - Luke R Tembrock
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Sen Li
- The College of Horticulture, Shanxi Agricultural University, Taigu, 030801, Shanxi, China.
| | - Cuihua Gu
- School of Landscape and Architecture, Zhejiang Provincial Key Laboratory of Germplasm Innovation and Utilization for Garden Plants, Key Laboratory of National Forestry and Grassland Administration on Germplasm Innovation and Utilization for Southern Garden Plants, Zhejiang A & F University, Hangzhou, 311300, China.
| | - Xuezhu Liao
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China.
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Marchica A, Loré S, Cotrozzi L, Lorenzini G, Nali C, Pellegrini E, Remorini D. Early Detection of Sage ( Salvia officinalis L.) Responses to Ozone Using Reflectance Spectroscopy. PLANTS (BASEL, SWITZERLAND) 2019; 8:E346. [PMID: 31547452 PMCID: PMC6784234 DOI: 10.3390/plants8090346] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/02/2019] [Accepted: 09/04/2019] [Indexed: 11/24/2022]
Abstract
Advancements in techniques to rapidly and non-destructively detect the impact of tropospheric ozone (O3) on crops are required. This study demonstrates the capability of full-range (350-2500 nm) reflectance spectroscopy to characterize responses of asymptomatic sage leaves under an acute O3 exposure (200 ppb for 5 h). Using partial least squares regression, spectral models were developed for the estimation of several traits related to photosynthesis, the oxidative pressure induced by O3, and the antioxidant mechanisms adopted by plants to cope with the pollutant. Physiological traits were well predicted by spectroscopic models (average model goodness-of-fit for validation (R2): 0.65-0.90), whereas lower prediction performances were found for biochemical traits (R2: 0.42-0.71). Furthermore, even in the absence of visible symptoms, comparing the full-range spectral profiles, it was possible to distinguish with accuracy plants exposed to charcoal-filtered air from those exposed to O3. An O3 effect on sage spectra was detectable from 1 to 5 h from the beginning of the exposure, but ozonated plants quickly recovered after the fumigation. This O3-tolerance was confirmed by trends of vegetation indices and leaf traits derived from spectra, further highlighting the capability of reflectance spectroscopy to early detect the responses of crops to O3.
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Affiliation(s)
- Alessandra Marchica
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
| | - Silvia Loré
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
| | - Lorenzo Cotrozzi
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
| | - Giacomo Lorenzini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
- CIRSEC, Centre for Climate Change Impact, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
- Nutrafood Research Center, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
| | - Cristina Nali
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
- CIRSEC, Centre for Climate Change Impact, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
- Nutrafood Research Center, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
| | - Elisa Pellegrini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
- CIRSEC, Centre for Climate Change Impact, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
- Nutrafood Research Center, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
| | - Damiano Remorini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
- CIRSEC, Centre for Climate Change Impact, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
- Nutrafood Research Center, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
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Deacon NJ, Grossman JJ, Cavender‐Bares J. Drought and freezing vulnerability of the isolated hybrid aspen Populus x smithii relative to its parental species, P. tremuloides and P. grandidentata. Ecol Evol 2019; 9:8062-8074. [PMID: 31380071 PMCID: PMC6662423 DOI: 10.1002/ece3.5364] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/09/2019] [Accepted: 05/14/2019] [Indexed: 11/12/2022] Open
Abstract
AIM We assessed the vulnerability of an isolated, relictual Pleistocene hybrid aspen population of conservation interest (Populus x. smithii) and the nearest populations of its parent species (Populus grandidentata and Populus tremuloides) to springtime post-bud break freezing and growing season drought stress. Response to these stressors in the three taxa was compared in terms of avoidance and tolerance. LOCATION North American Midwest; USA. METHODS Unique genets from the hybrid Niobrara River population and from the two parental populations were propagated in a common garden from rhizome cuttings. We tracked their phenology before and after bud break and measured their vulnerability to freezing (stem electrolyte leakage and leaf chlorophyll fluorescence) and to drought (stem hydraulic conductance, leaf osmotic potential, stomatal pore index, and gas exchange). RESULTS Populus grandidentata was slower to leaf out, showed lower vulnerability to stem freezing and drought-induced cavitation, but exhibited a lower capacity to tolerate drought stress through leaf resistance traits compared to P. tremuloides. Hybrids were similar to P. grandidentata in their overwintering strategy, exhibiting later bud break, and in their higher resistance to stem freezing damage, but they were more similar to P. tremuloides in their higher vulnerability to drought-induced cavitation. The hybrids shared various leaf-level gas exchange traits with both parents. All aspens showed limited loss of leaf photosynthetic function following moderate freezing. MAIN CONCLUSIONS The Niobrara River hybrid population is vulnerable to drought due to its combination of inherited drought avoidance and tolerance traits. As climate changes, P. x smithii will likely suffer from increased drought stress, while being unaffected by frost during warmer springs. The two parental species contrast in their survival mechanisms in response to climatic stress, with P. tremuloides tending toward freezing tolerance but drought avoidance and P. grandidentata tending toward freezing avoidance and drought tolerance.
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Affiliation(s)
- Nicholas J. Deacon
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMinnesota
- Present address:
Minneapolis Community and Technical College1501 Hennepin AvenueMinneapolis55403MN
| | - Jake J. Grossman
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMinnesota
- Present address:
Arnold Arboretum of Harvard University125 ArborwayBoston02130MA
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Robertson JM, Cahlander-Mooers AR, Dixon MD. Effects of Management Treatments on Regeneration of a Geographically Disjunct, Relictual Hybrid Aspen (Populus xsmithii) Population in the Central Great Plains, USA. ENVIRONMENTAL MANAGEMENT 2018; 62:906-914. [PMID: 30159704 DOI: 10.1007/s00267-018-1092-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 08/04/2018] [Indexed: 06/08/2023]
Abstract
Populus xsmithii is an uncommon hybrid of quaking aspen (Populus tremuloides) and bigtooth aspen (Populus grandidentata). Like its parents, Populus xsmithii is an early successional member of boreal forest communities, dependent on disturbance events that clear areas of competitive stems and spur an increase in clonal suckering. In recent years, aspen dieback has been noted across much of the western United States, a condition characterized by mortality of older stems and a lack of recruitment of suckers to maturity. In the Niobrara River Valley of Cherry County, Nebraska, USA, a disjunct population of Pleistocene relict Populus xsmithii has been targeted for management via clearing of competitive conifer species and establishment of fenced refugia to protect suckers from herbivory. The stands currently contain abundant suckers, which occur in three types of sites: the fenced refugia created by managers, the open habitat cleared of other species in the stands, and the woodpiles left by said clearing. This study assessed the growth and vigor of these aspen suckers over a nine-month period (summer 2013-spring 2014) and compared the effects of different site treatments. We found that aspen suckers in the open areas were significantly shorter, had smaller basal diameter, and had higher damage scores than those in the two protected site types (fenced and woodpile). Because this population is on the margin of the distribution for aspen, evaluating the effectiveness of management techniques will provide valuable information for those who seek to ensure the survival of this aspen population and others.
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Affiliation(s)
- James M Robertson
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA
- Eco-Asset Midwest, Sioux Falls, SD, 57103, USA
| | - Alex R Cahlander-Mooers
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA
- Westwood Surveying and Engineering, Minneapolis, MN, 55344, USA
| | - Mark D Dixon
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA.
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