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Bailey EC, Thacker E, Monaco TA, Veblen KE. Transplanted sagebrush "wildlings" exhibit higher survival than greenhouse-grown tubelings yet both recruit new plants. BMC Ecol Evol 2024; 24:50. [PMID: 38649814 PMCID: PMC11034100 DOI: 10.1186/s12862-024-02236-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 04/04/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Land uses such as crop production, livestock grazing, mining, and urban development have contributed to degradation of drylands worldwide. Loss of big sagebrush (Artemisia tridentata) on disturbed drylands across the western U.S. has prompted massive efforts to re-establish this foundational species. There has been growing interest in avoiding the severe limitations experienced by plants at the seed and seedling stages by instead establishing plants from containerized greenhouse seedlings ("tubelings"). In some settings, a potential alternative approach is to transplant larger locally-collected plants ("wildlings"). We compared the establishment of mountain big sagebrush (A. tridentata ssp. vaseyana) from tubelings vs. wildlings in southeastern Idaho. A mix of native and non-native grass and forb species was drill-seeded in a pasture previously dominated by the introduced forage grass, smooth brome (Bromus inermis). We then established 80 m x 80 m treatment plots and planted sagebrush tubelings (n = 12 plots, 1200 plants) and wildlings (n = 12 plots, 1200 plants). We also established seeded plots (n = 12) and untreated control plots (n = 6) for long-term comparison. We tracked project expenses in order to calculate costs of using tubelings vs. wildlings as modified by probability of success. RESULTS There was high (79%) tubeling and low (10%) wildling mortality within the first year. Three years post-planting, chance of survival for wildlings was significantly higher than that of tubelings (85% and 14% respectively). Despite high up-front costs of planting wildlings, high survival rates resulted in their being < 50% of the cost of tubelings on a per-surviving plant basis. Additionally, by the third year post-planting 34% of surviving tubelings and 95% of surviving wildlings showed evidence of reproduction (presence / absence of flowering stems), and the two types of plantings recruited new plants via seed (3.7 and 2.4 plants, respectively, per surviving tubeling/wildling). CONCLUSIONS Our results indicate that larger plants with more developed root systems (wildlings) may be a promising avenue for increasing early establishment rates of sagebrush plants in restoration settings. Our results also illustrate the potential for tubelings and wildlings to improve restoration outcomes by "nucleating" the landscape via recruitment of new plants during ideal climate conditions.
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Affiliation(s)
- Elizabeth C Bailey
- Dept. of Wildland Resources, Utah State University, 5230 Old Main Hill, Logan, UT, 84322, USA
- Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT, 84322, USA
- SWCA Environmental Consultants, 7210 Placid St, Las Vegas, NV, 89119, USA
| | - Eric Thacker
- Dept. of Wildland Resources, Utah State University, 5230 Old Main Hill, Logan, UT, 84322, USA
| | - Thomas A Monaco
- U.S. Department of Agriculture, Agricultural Research Service, Forage and Range Research Laboratory, Utah State University, Logan, UT, 84322, USA
| | - Kari E Veblen
- Dept. of Wildland Resources, Utah State University, 5230 Old Main Hill, Logan, UT, 84322, USA.
- Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT, 84322, USA.
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Rajapakshe RPVGSW, Tomlinson S, Tudor EP, Turner SR, Elliott CP, Lewandrowski W. Same, same, but different: dissimilarities in the hydrothermal germination performance of range-restricted endemics emerge despite microclimatic similarities. CONSERVATION PHYSIOLOGY 2024; 12:coae009. [PMID: 38487732 PMCID: PMC10939308 DOI: 10.1093/conphys/coae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 01/17/2024] [Accepted: 01/24/2024] [Indexed: 03/17/2024]
Abstract
Seed germination responses for most narrow-range endemic species are poorly understood, imperilling their conservation management in the face of warming and drying terrestrial ecosystems. We quantified the realized microclimatic niches and the hydrothermal germination thresholds in four threatened taxa (Tetratheca erubescens, Tetratheca harperi, Tetratheca paynterae subsp. paynterae and Tetratheca aphylla subsp. aphylla) that are restricted to individual Banded Ironstone Formations in Western Australia. While T. aphylla subsp. aphylla largely failed to germinate in our trials, all other species demonstrated extended hydrothermal time accumulation (186-500°C MPa days), cool minimum temperatures (7.8-8.5°C), but broad base water potential thresholds (-2.46 to -5.41 MPa) under which germination occurred. These slow germination dynamics are suggestive of cool and wet winter months, where soil moisture is retained to a greater capacity in local microsites where these species occur, rather than the warmer and drier conditions in the surrounding arid environment. Hydrothermal time-to-event modelling showed that each species occupied unique hydrothermal germination niches, which correspond with the microclimatic differences the species are exposed to. Our results provide a baseline understanding for environmental and germination thresholds that govern the recruitment, and ultimately the population structure and persistence, of these short-range endemic plants. In addition, our results can aid future conservation, as well as restoration actions such as translocation to bolster population numbers and to mitigate against losses due to anthropogenic disturbance and global environmental change.
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Affiliation(s)
- Rajapakshe P V G S W Rajapakshe
- ARC Centre for Mine Site Restoration, Curtin University, Bentley, 6102, Australia
- School of Molecular and Life Sciences, Curtin University, Bentley, 6102, Australia
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, 6005, Australia
| | - Sean Tomlinson
- School of Molecular and Life Sciences, Curtin University, Bentley, 6102, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, 5000, Australia
| | - Emily P Tudor
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, 6005, Australia
- School of Biological Sciences, University of Western Australia, Crawley, 6009, Australia
| | - Shane R Turner
- ARC Centre for Mine Site Restoration, Curtin University, Bentley, 6102, Australia
- School of Molecular and Life Sciences, Curtin University, Bentley, 6102, Australia
| | - Carole P Elliott
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, 6005, Australia
- School of Biological Sciences, University of Western Australia, Crawley, 6009, Australia
| | - Wolfgang Lewandrowski
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, 6005, Australia
- School of Biological Sciences, University of Western Australia, Crawley, 6009, Australia
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Just M, Turner S, Cross A, Lewandrowski W, Pedrini S, Dixon K. Germination physiology of Cochlospermum fraseri (Bixaceae), a deciduous tree from Northern Australia with physical seed dormancy. CONSERVATION PHYSIOLOGY 2023; 11:coad057. [PMID: 37671236 PMCID: PMC10476509 DOI: 10.1093/conphys/coad057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/28/2023] [Accepted: 07/19/2023] [Indexed: 09/07/2023]
Abstract
Cochlospermum fraseri ('Kapok', Bixaceae) is a deciduous tree widely distributed throughout semi-arid and monsoon tropical northern Australia, and an important species for ecological restoration in the region. We aimed to better understand the seed biology and ecology of C. fraseri to determine the mechanisms by which seed dormancy might be alleviated, and the conditions that support germination to inform the use of this species in restoration. Dormancy breaking treatments (wet heat, dry heat, scarification) commonly applied to species with physical seed dormancy (PY) were tested along with stratification at 5-35°C (nine treatments). Following dormancy alleviation, seeds were germinated at nine temperatures (5 to 40°C) and five water potentials (0 to -0.8 MPa) to understand environmental thresholds that regulate germination physiology in non-dormant seeds. A proportion of seeds (<0.3) lose dormancy naturally in response to warm (25 to 35°C) moist conditions, which dislodges the hypostase plug that prevents water uptake, whilst neither dry (≥100°C) nor wet (~100°C) heat were effective. Dormancy loss was also achieved by exposing seeds to concentrated (95-98% v/v) sulphuric acid for 3-7 hours, after which high proportions (>0.75) of germination were observed. Cochlospermum fraseri seeds possess PY, which is alleviated by seasonal temperatures that occur when soil moisture is high, allowing seeds to employ a risk-adverse strategy and maximize establishment success in episodic environments with stochastic rainfall events. The understanding of dormancy alleviation requirements gained here adds to our knowledge of PY worldwide and recruitment dynamics in the Australian monsoonal tropics and will aid land managers and restoration practitioners by informing both seeding sites and optimal time for in situ sowing as well as the potential capacity of this species to form a persistent soil seed bank.
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Affiliation(s)
- Michael Just
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
| | - Shane Turner
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
| | - Adam Cross
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
- Ecological Health Network, 1330 Beacon St, Suite 355a, Brookline, Massachusetts 02446, United States of America
| | - Wolfgang Lewandrowski
- Department of Biodiversity, Conservation and Attractions, Kings Park Science, Fraser Avenue, Kings Park, Western Australia 6005, Australia
- School of Biological Sciences, University of Western Australia, Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Simone Pedrini
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
| | - Kingsley Dixon
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
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Filipe JC, Ahrens CC, Byrne M, Hardy G, Rymer PD. Germination temperature sensitivity differs between co-occurring tree species and climate origins resulting in contrasting vulnerability to global warming. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2023; 4:146-162. [PMID: 37362420 PMCID: PMC10290426 DOI: 10.1002/pei3.10108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 03/20/2023] [Accepted: 04/04/2023] [Indexed: 06/28/2023]
Abstract
Climate change is shifting temperatures from historical patterns, globally impacting forest composition and resilience. Seed germination is temperature-sensitive, making the persistence of populations and colonization of available habitats vulnerable to warming. This study assessed germination response to temperature in foundation trees in south-western Australia's Mediterranean-type climate forests (Eucalyptus marginata (jarrah) and Corymbia calophylla (marri)) to estimate the thermal niche and vulnerability among populations. Seeds from the species' entire distribution were collected from 12 co-occurring populations. Germination thermal niche was investigated using a thermal gradient plate (5-40°C). Five constant temperatures between 9 and 33°C were used to test how the germination niche (1) differs between species, (2) varies among populations, and (3) relates to the climate of origin. Germination response differed among species; jarrah had a lower optimal temperature and thermal limit than marri (T o 15.3°C, 21.2°C; ED50 23.4°C, 31°C, respectively). The thermal limit for germination differed among populations within both species, yet only marri showed evidence for adaptation to thermal origins. While marri has the capacity for germination at higher thermal temperatures, jarrah is more vulnerable to global warming exceeding safety margins. This discrepancy is predicted to alter species distributions and forest composition in the future.
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Affiliation(s)
- João C. Filipe
- Department of Biodiversity, Conservation and AttractionsBiodiversity and Conservation SciencePerthWestern AustraliaAustralia
- Centre for Terrestrial Ecosystem Science and SustainabilityHarry Butler InstituteMurdoch UniversityMurdochWestern AustraliaAustralia
| | - Collin C. Ahrens
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityRichmondNew South WalesAustralia
- School of Biotechnology & Biomolecular SciencesUniversity of New South WalesSydneyNew South WalesAustralia
- Research Centre for Ecosystem ResilienceRoyal Botanic Gardens and Domain TrustSydneyNew South WalesAustralia
- Cesar AustraliaBrunswickVictoriaAustralia
| | - Margaret Byrne
- Department of Biodiversity, Conservation and AttractionsBiodiversity and Conservation SciencePerthWestern AustraliaAustralia
| | - Giles Hardy
- Centre for Terrestrial Ecosystem Science and SustainabilityHarry Butler InstituteMurdoch UniversityMurdochWestern AustraliaAustralia
| | - Paul D. Rymer
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityRichmondNew South WalesAustralia
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Rajapakshe RPVGSW, Cross AT, Turner SR, Tomlinson S. Understanding the interplay of temperature and moisture on the germination niche to improve management of threatened species impacted by mining. Restor Ecol 2022. [DOI: 10.1111/rec.13708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Rajapakshe P. V. G. S. W. Rajapakshe
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences Curtin University Bentley WA 6102 Australia
- School of Molecular and Life Sciences Curtin University Bentley Western Australia 6102 Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions Kings Park Western Australia 6005 Australia
| | - Adam T. Cross
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences Curtin University Bentley WA 6102 Australia
- School of Molecular and Life Sciences Curtin University Bentley Western Australia 6102 Australia
- EcoHealth Network, 1330 Beacon St, Suite 355a Brookline MA 02446 United States
| | - Shane R. Turner
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences Curtin University Bentley WA 6102 Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions Kings Park Western Australia 6005 Australia
- School of Biological Sciences University of Western Australia Crawley Western Australia 6009 Australia
| | - Sean Tomlinson
- School of Molecular and Life Sciences Curtin University Bentley Western Australia 6102 Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions Kings Park Western Australia 6005 Australia
- School of Biological Sciences, University of Adelaide, North Terrace Adelaide South Australia 5000 Australia
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Jiang L, Wen Z, Zhang Y, Zhao Z, Tanveer M, Tian C, Wang L. Transgenerational Effects of Maternal Water Condition on the Growth, C:N Stoichiometry and Seed Characteristics of the Desert Annual Atriplex aucheri. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112362. [PMID: 34834724 PMCID: PMC8620486 DOI: 10.3390/plants10112362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Water conditions directly affect plant growth and thus modify reproduction allocation. However, little is known about the transgenerational effects of water conditions on xerophytes. The desert annual Atriplex aucheri produces three types of seeds (A: dormant, ebracteate black seeds; B: dormant, bracteolate black seeds; C: non-dormant, bracteolate brown seeds) on a single plant. The aim of this study was to investigate the effects of low/high water treatment (thereafter progeny water treatment) on aboveground biomass, C:N stoichiometry, and offspring seed characteristics of A. aucheri grown from brown seeds whose mother plants were under low/high water treatment (thereafter maternal water treatment). Progeny water only affected shoot dry weight and seed allocation of type A. Under low progeny water treatment, plants from parents with low maternal water treatment had the lowest biomass. Maternal water did not significantly influence the C and N content, however high maternal water increased the C:N ratio. Maternal water treatment did not significantly affect seed number. However, plants under low maternal and progeny water treatments had the lowest weight for type B seeds. When progeny plants were under low water treatment, seed allocation of type A, type B, and total seed allocation of plants under high maternal water were significantly lower than those of plants under low maternal water. These results indicate that water conditions during the maternal generation can dramatically contribute to progeny seed variation, but the transgenerational effects depend on the water conditions of progeny plants.
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Affiliation(s)
- Li Jiang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China; (L.J.); (Z.W.); (Z.Z.); (C.T.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhibin Wen
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China; (L.J.); (Z.W.); (Z.Z.); (C.T.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunling Zhang
- General Grassland Station of Xinjiang, Urumqi 830049, China;
| | - Zhenyong Zhao
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China; (L.J.); (Z.W.); (Z.Z.); (C.T.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mohsin Tanveer
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS 7001, Australia;
| | - Changyan Tian
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China; (L.J.); (Z.W.); (Z.Z.); (C.T.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lei Wang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi 830011, China; (L.J.); (Z.W.); (Z.Z.); (C.T.)
- University of Chinese Academy of Sciences, Beijing 100049, China
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Germination response to water availability in populations of Festuca pallescens along a Patagonian rainfall gradient based on hydrotime model parameters. Sci Rep 2021; 11:10653. [PMID: 34017012 PMCID: PMC8137931 DOI: 10.1038/s41598-021-89901-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 05/04/2021] [Indexed: 11/22/2022] Open
Abstract
Sensitivity to water availability is a key physiological trait for grassland species located in arid and semiarid environments, where successful germination is closely related to rainfall dynamics. Festuca pallescens inhabits diverse environments along a steep precipitation gradient in North Patagonia, thus offering a suitable model for the study of germination behavior in response to water availability. By analyzing germination in nine populations using a hydrotime model approach, we aimed to find within-species variation. Seed population behavior was analyzed under different hydric conditions using hydrotime model parameters (hydrotime, mean base water potential and its standard deviation). We estimated the mean base water potential for F. pallescens (ψb(50) = − 2.79 ± 0.45 MPa), which did not differ significantly between populations. However, the hydrotime parameter (θH) varied markedly, suggesting physiological adaptation to local environments. Higher values of θH were found in populations located at the extremes of the distribution gradient, indicating that germination may be prevented or delayed in conditions that are suboptimal for the species. Since the variation in hydrotime model parameters did not follow a cline, micro-environmental cues may have the greatest influence on the physiological behavior of the species, rather than the macroscale rainfall gradient.
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Effect of shade and precipitation on germination and seedling establishment of dominant plant species in an Andean arid region, the Bolivian Prepuna. PLoS One 2021; 16:e0248619. [PMID: 33788871 PMCID: PMC8011746 DOI: 10.1371/journal.pone.0248619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 03/02/2021] [Indexed: 11/25/2022] Open
Abstract
Germination and seedling establishment are two critical processes in the life cycle of plants. Seeds and seedlings must pass through a series of abiotic and biotic filters in order to recruit as members of their communities. These processes are part of the regeneration niche of the species. In arid regions, the regeneration niche is frequently associated to facilitation by shade. Facilitation is a positive interaction between plants, in which one of them acts as a benefactor (the nurse) of the other (the beneficiary). The result of this interaction can be reflected in the increased growth, survival, and/or reproduction of the beneficiary plant. In this study, we determined experimentally the effect of shade and irrigation on the germination and early survival of dominant species of a semi-arid Andean region, the Bolivian Prepuna. An experiment with Acacia feddeana, Prosopis ferox, Cercidium andicola (woody species), Parodia maassii, and Oreocereus celsianus (cactus species) was carried out at an experimental garden in La Paz, Bolivia, with a bifactorial design, considering shaded and unshaded pots, subjected to two irrigation treatments (≈50 and 80 mm of rainfall during the whole study period). Microenvironmental conditions did not affect the seed germination of the woody species. However, they showed differences in seedling survival: A. feddeana survived better under shade, whereas P. ferox and C. andicola survived better without shade. Cercidium andicola, compared to P. ferox, was more affected by shade and low irrigation. Although germination success of cacti was low, both species germinated better under shade and with high irrigation. These results showed differences in the regeneration niche of dominant species of the Prepuna which may favor their coexistence and which may be characteristic of other dry Andean regions.
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Burnette TE, Eckhart VM. Evolutionary divergence of potential drought adaptations between two subspecies of an annual plant: Are trait combinations facilitated, independent, or constrained? AMERICAN JOURNAL OF BOTANY 2021; 108:309-319. [PMID: 33524185 PMCID: PMC7986167 DOI: 10.1002/ajb2.1607] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 10/14/2020] [Indexed: 05/17/2023]
Abstract
PREMISE Whether drought-adaptation mechanisms tend to evolve together, evolve independently, or evolve constrained by genetic architecture is incompletely resolved, particularly for water-relations traits besides gas exchange. We addressed this issue in two subspecies of Clarkia xantiana (Onagraceae), California winter annuals that separated approximately 65,000 years ago and are adapted, partly by differences in flowering time, to native ranges differing in precipitation. METHODS In these subspecies and in recombinant inbred lines (RILs) from a cross between them, we scored traits related to drought adaptation (timing of seed germination and of flowering, succulence, pressure-volume curve variables) in common environments. RESULTS The subspecies native to more arid environments (parviflora) exhibited slower seed germination in saturated conditions, earlier flowering, and greater succulence, likely indicating superior drought avoidance, drought escape, and dehydration resistance via water storage. The other subspecies (xantiana) had lower osmotic potential at full turgor and lower water potential at turgor loss, implying superior dehydration tolerance. Genetic correlations among RILs suggest facilitated evolution of some trait combinations and independence of others. Where genetic correlations exist, subspecies differences fell along them, with the exception of differences in succulence and turgor loss point. In that case, subspecies difference overcame genetic correlations, possibly reflecting strong selection and/or antagonistic genetic correlations with other traits. CONCLUSIONS Clarkia xantiana subspecies' differ in multiple mechanisms of drought adaptation. Genetic architecture generally does not seem to have constrained the evolution of these mechanisms, and it may have facilitated the evolution of some of trait combinations.
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Affiliation(s)
- Timothy E. Burnette
- Division of Biological SciencesUniversity of MontanaMissoulaMT59802USA
- Department of BiologyGrinnell CollegeGrinnellIA50112USA
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10
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Burnette TE, Eckhart VM. Evolutionary divergence of potential drought adaptations between two subspecies of an annual plant: Are trait combinations facilitated, independent, or constrained? AMERICAN JOURNAL OF BOTANY 2021; 108:309-319. [PMID: 33524185 DOI: 10.5061/dryad.k3j9kd55k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 10/14/2020] [Indexed: 05/28/2023]
Abstract
PREMISE Whether drought-adaptation mechanisms tend to evolve together, evolve independently, or evolve constrained by genetic architecture is incompletely resolved, particularly for water-relations traits besides gas exchange. We addressed this issue in two subspecies of Clarkia xantiana (Onagraceae), California winter annuals that separated approximately 65,000 years ago and are adapted, partly by differences in flowering time, to native ranges differing in precipitation. METHODS In these subspecies and in recombinant inbred lines (RILs) from a cross between them, we scored traits related to drought adaptation (timing of seed germination and of flowering, succulence, pressure-volume curve variables) in common environments. RESULTS The subspecies native to more arid environments (parviflora) exhibited slower seed germination in saturated conditions, earlier flowering, and greater succulence, likely indicating superior drought avoidance, drought escape, and dehydration resistance via water storage. The other subspecies (xantiana) had lower osmotic potential at full turgor and lower water potential at turgor loss, implying superior dehydration tolerance. Genetic correlations among RILs suggest facilitated evolution of some trait combinations and independence of others. Where genetic correlations exist, subspecies differences fell along them, with the exception of differences in succulence and turgor loss point. In that case, subspecies difference overcame genetic correlations, possibly reflecting strong selection and/or antagonistic genetic correlations with other traits. CONCLUSIONS Clarkia xantiana subspecies' differ in multiple mechanisms of drought adaptation. Genetic architecture generally does not seem to have constrained the evolution of these mechanisms, and it may have facilitated the evolution of some of trait combinations.
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Affiliation(s)
- Timothy E Burnette
- Division of Biological Sciences, University of Montana, Missoula, MT, 59802, USA
- Department of Biology, Grinnell College, Grinnell, IA, 50112, USA
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Renzi JP, Duchoslav M, Brus J, Hradilová I, Pechanec V, Václavek T, Machalová J, Hron K, Verdier J, Smýkal P. Physical Dormancy Release in Medicago truncatula Seeds Is Related to Environmental Variations. PLANTS (BASEL, SWITZERLAND) 2020; 9:E503. [PMID: 32295289 PMCID: PMC7238229 DOI: 10.3390/plants9040503] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/13/2020] [Accepted: 04/13/2020] [Indexed: 12/26/2022]
Abstract
Seed dormancy and timing of its release is an important developmental transition determining the survival of individuals, populations, and species in variable environments. Medicago truncatula was used as a model to study physical seed dormancy at the ecological and genetics level. The effect of alternating temperatures, as one of the causes releasing physical seed dormancy, was tested in 178 M. truncatula accessions over three years. Several coefficients of dormancy release were related to environmental variables. Dormancy varied greatly (4-100%) across accessions as well as year of experiment. We observed overall higher physical dormancy release under more alternating temperatures (35/15 °C) in comparison with less alternating ones (25/15 °C). Accessions from more arid climates released dormancy under higher experimental temperature alternations more than accessions originating from less arid environments. The plasticity of physical dormancy can probably distribute the germination through the year and act as a bet-hedging strategy in arid environments. On the other hand, a slight increase in physical dormancy was observed in accessions from environments with higher among-season temperature variation. Genome-wide association analysis identified 136 candidate genes related to secondary metabolite synthesis, hormone regulation, and modification of the cell wall. The activity of these genes might mediate seed coat permeability and, ultimately, imbibition and germination.
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Affiliation(s)
- Juan Pablo Renzi
- Instituto Nacional de Tecnología Agropecuaria, Hilario Ascasubi 8142, Argentina;
| | - Martin Duchoslav
- Department of Botany, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic; (M.D.); (I.H.)
| | - Jan Brus
- Department of Geoinformatics, Palacký University, 17. listopadu 50, 771 46 Olomouc, Czech Republic; (J.B.); (V.P.)
| | - Iveta Hradilová
- Department of Botany, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic; (M.D.); (I.H.)
| | - Vilém Pechanec
- Department of Geoinformatics, Palacký University, 17. listopadu 50, 771 46 Olomouc, Czech Republic; (J.B.); (V.P.)
| | - Tadeáš Václavek
- Department of Mathematical Analysis and Applications of Mathematics, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic; (T.V.); (J.M.); (K.H.)
| | - Jitka Machalová
- Department of Mathematical Analysis and Applications of Mathematics, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic; (T.V.); (J.M.); (K.H.)
| | - Karel Hron
- Department of Mathematical Analysis and Applications of Mathematics, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic; (T.V.); (J.M.); (K.H.)
| | - Jerome Verdier
- UMR 1345 Institut de Recherche en Horticulture et Semences, Agrocampus Ouest, INRA, Université d’Angers, SFR 4207 QUASAV, 49070 Beaucouzé, France;
| | - Petr Smýkal
- Department of Botany, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic; (M.D.); (I.H.)
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