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Zhang L, Xu C, Liu H, Wu Q, Tao J, Zhang K. Intermediate complex morphophysiological dormancy in seeds of Aconitum barbatum (Ranunculaceae). BMC Plant Biol 2023; 23:350. [PMID: 37407945 DOI: 10.1186/s12870-023-04357-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 06/21/2023] [Indexed: 07/07/2023]
Abstract
BACKGROUND Seed dormancy and germination are key components of plant regeneration strategies. Aconitum barbatum is a plant commonly found in northeast China. Although it has potential for use in gardening and landscaping, its seed dormancy and regeneration strategy, which adapt to its natural habitat, are not well understood. Our aim was to identify conditions for breaking A. barbatum seed dormancy and determine its dormancy type. Embryo growth and germination were determined by collecting seeds over time in the field. Laboratory experiments that control light, temperature, and stratification period were conducted to assess dormancy breaking and germination, and GA3 was used to identify dormancy type. RESULTS Seeds of A. barbatum have undeveloped embryos with physiological dormancy at maturity in autumn. The embryo-to-seed length ratio increases from 0.33 to 0.78 before the emergence of the radical. Under natural environmental conditions, embryo development begins in early winter. Laboratory experiments have shown that long-term incubation under 4 °C (cold stratification) promotes embryo development and seed dormancy break. With an extension of cold stratification, an increase in germination percentages was observed when seeds were transferred from 4 °C to warmer temperatures. Seeds exposed to light during incubation show a higher germination percentage than those kept in the dark. Seed germination can also be enhanced by a 100 mg/L GA3 concentration. CONCLUSIONS Seeds of A. barbatum display intermediate complex morphophysiological dormancy at maturity. In addition to the underdeveloped embryo, there are also physiological barriers that prevent the embryo from germinating. Dormancy breaking of A. barbatum seeds can be achieved by natural winter cold stratification, allowing seeds to germinate and sprout seedlings at the beginning of the following growing season. Our findings provide valuable insights into the seed dormancy and regeneration strategy of A. barbatum, which could facilitate its effective utilization in gardening and landscaping.
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Affiliation(s)
- Lei Zhang
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, 225009, China
| | - Chaohan Xu
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, 225009, China
| | - Huina Liu
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, 225009, China
| | - Qingqing Wu
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, 225009, China
| | - Jun Tao
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, 225009, China.
| | - Keliang Zhang
- College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou, 225009, China.
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2
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Berto B, Erickson TE, Ritchie AL. Improving Seed Morphology and Germination Potential in Australian Native Grasses Using Seed Enhancement Technologies. Plants (Basel) 2023; 12:2432. [PMID: 37446992 DOI: 10.3390/plants12132432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 07/15/2023]
Abstract
Difficult to handle seed material and poor germination commonly limit the uptake of native grasses in restoration and commercial-scale seeding efforts. Seed enhancement technologies (SETs) offer valuable solutions for improving the handling of seed material and optimising germination. This study considered eight widespread Australian native grasses; two representative of Mediterranean to temperate climates ('cool-climate' species) and six representative of arid to subtropical climates ('warm-climate' species). Through a series of experiments, this study logically selected and applied SET treatments to improve seed handling and germination for each study species. Seed handling was prioritised and addressed using flash flaming and/or acid digestion, while hydropriming was used following seed-handling treatments to enhance germination. Flash flaming and acid digestion were both applied to successfully reduce or remove bulky floret structures while maintaining or improving germination. Flaming at 110 ± 10 °C with continuous exposure for 10 min and acid digestion concentrations of 75-80% with exposure times of 1-2.5 min were generally successful. Sub-optimal concentrations of sulphuric acid often compromised germination. Hydropriming did not improve germination outcomes when applied following flaming or acid digestion. Optimising SETs for germination, emergence and establishment in different environments, and the viability and costs of application on larger seed batches are key considerations for the implementation and upscaling of SETs in the future.
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Affiliation(s)
- Bianca Berto
- School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, WA 6005, Australia
| | - Todd E Erickson
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, WA 6005, Australia
- Centre for Engineering Innovation: Agriculture and Ecological Restoration, School of Agriculture and Environment, The University of Western Australia, Crawley, WA 6009, Australia
| | - Alison L Ritchie
- School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, WA 6005, Australia
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3
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Wright BR, Nipper M, Nipper N, Merson SD, Guest T. Mortality rates of desert vegetation during high‐intensity drought at
Uluru‐Kata
Tjuta National Park, Central Australia. AUSTRAL ECOL 2023. [DOI: 10.1111/aec.13290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- Boyd R. Wright
- Uluru‐Kata Tjuta National Park Yulara Northwest Territories Australia
- School of Agriculture and Food Science University of Queensland Brisbane Queensland Australia
- Botany, School of Environmental and Rural Science University of New England Armidale New South Wales Australia
| | - Martin Nipper
- Mutitjulu Community Ranger Program, Mutitjulu Community Yulara Northwest Territories Australia
| | - Nathan Nipper
- Mutitjulu Community Ranger Program, Mutitjulu Community Yulara Northwest Territories Australia
| | | | - Tracey Guest
- Uluru‐Kata Tjuta National Park Yulara Northwest Territories Australia
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4
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Tomlinson S, Tudor EP, Turner SR, Cross S, Riviera F, Stevens J, Valliere J, Lewandrowski W. Leveraging the value of conservation physiology for ecological restoration. Restor Ecol 2021. [DOI: 10.1111/rec.13616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sean Tomlinson
- School of Biological Sciences, University of Adelaide, North Terrace Adelaide South Australia 5000 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
| | - Emily P. Tudor
- 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 Western Australia Crawley Western Australia 6009 Australia
| | - Shane R. Turner
- Kings Park Science, Department of Biodiversity, Conservation and Attractions Kings Park, Western Australia 6005 Australia
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
- School of Biological Sciences, University of Western Australia Crawley Western Australia 6009 Australia
| | - Sophie Cross
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
| | - Fiamma Riviera
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
- School of Biological Sciences, University of Western Australia Crawley Western Australia 6009 Australia
| | - Jason Stevens
- Kings Park Science, Department of Biodiversity, Conservation and Attractions Kings Park, Western Australia 6005 Australia
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
- School of Biological Sciences, University of Western Australia Crawley Western Australia 6009 Australia
| | - Justin Valliere
- Department of Biology California State University Dominguez Hills Carson California 90747 US
| | - Wolfgang Lewandrowski
- 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
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5
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Lewandrowski W, Stevens JC, Webber BL, L. Dalziell E, Trudgen MS, Bateman AM, Erickson TE. Global change impacts on arid zone ecosystems: Seedling establishment processes are threatened by temperature and water stress. Ecol Evol 2021; 11:8071-8084. [PMID: 34188872 PMCID: PMC8216921 DOI: 10.1002/ece3.7638] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 03/31/2021] [Accepted: 04/17/2021] [Indexed: 11/24/2022] Open
Abstract
Recruitment for many arid-zone plant species is expected to be impacted by the projected increase in soil temperature and prolonged droughts associated with global climate change. As seed dormancy is considered a strategy to avoid unfavorable conditions, understanding the mechanisms underpinning vulnerability to these factors is critical for plant recruitment in intact communities, as well as for restoration efforts in arid ecosystems. This study determined the effects of temperature and water stress on recruitment processes in six grass species in the genus Triodia R.Br. from the Australian arid zone. Experiments in controlled environments were conducted on dormant and less-dormant seeds at constant temperatures of 25°C, 30°C, 35°C, and 40°C, under well-watered (Ψsoil = -0.15 MPa) and water-limited (Ψsoil = -0.35 MPa) conditions. Success at three key recruitment stages-seed germination, emergence, and survival-and final seed viability of ungerminated seeds was assessed. For all species, less-dormant seeds germinated to higher proportions under all conditions; however, subsequent seedling emergence and survival were higher in the more dormant seed treatment. An increase in temperature (35-40°C) under water-limited conditions caused 95%-100% recruitment failure, regardless of the dormancy state. Ungerminated seeds maintained viability in dry soil; however, when exposed to warm (30-40°C) and well-watered conditions, loss of viability was greater from the less-dormant seeds across all species. This work demonstrates that the transition from seed to established seedling is highly vulnerable to microclimatic constraints and represents a critical filter for plant recruitment in the arid zone. As we demonstrate temperature and water stress-driven mortality between seeds and established seedlings, understanding how these factors influence recruitment in other arid-zone species should be a high priority consideration for management actions to mitigate the impacts of global change on ecosystem resilience. The knowledge gained from these outcomes must be actively incorporated into restoration initiatives.
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Affiliation(s)
- Wolfgang Lewandrowski
- Kings Park ScienceDepartment of Biodiversity, Conservation and AttractionsKings ParkWestern AustraliaAustralia
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Jason C. Stevens
- Kings Park ScienceDepartment of Biodiversity, Conservation and AttractionsKings ParkWestern AustraliaAustralia
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Bruce L. Webber
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
- CSIRO Health and BiosecurityFloreatWestern AustraliaAustralia
- Western Australian Biodiversity Science InstitutePerthWestern AustraliaAustralia
| | - Emma L. Dalziell
- Kings Park ScienceDepartment of Biodiversity, Conservation and AttractionsKings ParkWestern AustraliaAustralia
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Melinda S. Trudgen
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
- CSIRO Health and BiosecurityFloreatWestern AustraliaAustralia
| | - Amber M. Bateman
- Kings Park ScienceDepartment of Biodiversity, Conservation and AttractionsKings ParkWestern AustraliaAustralia
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Todd E. Erickson
- Kings Park ScienceDepartment of Biodiversity, Conservation and AttractionsKings ParkWestern AustraliaAustralia
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
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6
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Lucas‐Borja ME, Van Stan JT, Heydari M, Omidipour R, Rocha F, Plaza‐Alvarez PA, Zema DA, Muñoz‐Rojas M. Post‐fire restoration with contour‐felled log debris increases early recruitment of Spanish black pine (
Pinus nigra
Arn. ssp.
salzmannii
) in Mediterranean forests. Restor Ecol 2021. [DOI: 10.1111/rec.13338] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Manuel Esteban Lucas‐Borja
- Higher Technical School of Agricultural and Forestry Engineering Castilla‐La Mancha University, Campus Universitario s/n Albacete 02071 Spain
| | - John T. Van Stan
- Applied Coastal Research Laboratory Georgia Southern University, Savannah, GA, U.S.A
| | - Mehdi Heydari
- Forest Sciences Department, Faculty of Agriculture Ilam University Ilam Ilam Province 6939177111 Iran
| | - Reza Omidipour
- Department of Rangeland and Watershed Management, Faculty of Agriculture Ilam University Ilam 69315‐516 Iran
| | - Francisco Rocha
- Instituto Superior Técnico University of Lisbon Lisbon Portugal
| | - Pedro Antonio Plaza‐Alvarez
- Higher Technical School of Agricultural and Forestry Engineering Castilla‐La Mancha University, Campus Universitario s/n Albacete 02071 Spain
| | - Demetrio Antonio Zema
- Department AGRARIA Mediterranean University of Reggio Calabria, Località Feo di Vito Reggio Calabria I‐89122 Italy
| | - Miriam Muñoz‐Rojas
- Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences The UNSW, Sydney Sydney NSW 2052 Australia
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
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7
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Bell K, Driscoll DA, Patykowski J, Doherty TS. Abundance, Condition and Size of a Foundation Species Vary with Altered Soil Conditions, Remnant Type and Potential Competitors. Ecosystems 2021. [DOI: 10.1007/s10021-020-00598-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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8
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Stock E, Standish RJ, Muñoz-Rojas M, Bell RW, Erickson TE. Field-Deployed Extruded Seed Pellets Show Promise for Perennial Grass Establishment in Arid Zone Mine Rehabilitation. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.576125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Current methods of mine rehabilitation in the arid zone have a high failure rate at seedling emergence largely due to limited availability of topsoil and low water-holding capacity of alternative growth substrates such as mining overburden and tailings. Further, seedlings have consistently failed to emerge from seeds sown on the soil surface using traditional broadcasting methods. Seed pellets, formed by extruding soil mixtures and seeds into pellets, can potentially increase soil water uptake through enhanced soil-seed contact and thereby improve seedling emergence. We tested an extruded seed pelleting method in a three-factor field experiment (i.e., different pellet-soil mixtures, organic amendments, and simulated rainfall regimes) in north-western Australia. Given the observed lack of seedling emergence from broadcast seeds, the aims of the experiment were to assess: (i) the use of pellets to promote native seedling emergence and establishment and; (ii) the soil physico-chemical and microbiological changes that occur with this method of rehabilitation. The effects of pellet-soil mixtures, organic amendment, and rainfall regime on seedling emergence and survival of three native plant species suggest trade-offs among responses. Pellets made with a 1:1 blend of topsoil and a loamy-sand waste material had the highest seedling emergence, while 100% topsoil pellets had lower emergence probably because of hardsetting. Triodia pungens (a native grass) survived to the end of the experiment while Indigofera monophylla and Acacia inaequilatera (native shrubs) emerged but did not survive. Adding an organic amendment in the extruded pellet inhibited Triodia seedling emergence but increased soil microbial activity. Overall, extruded pellets made from a 1:1 blend showed promise for the establishment of Triodia seeds and beneficially, incorporates mine waste overburden and lesser amounts of topsoil. Further research is needed to improve pelleting production and to test the applicability of the method at scale, for different species and other ecosystem types.
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9
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Affiliation(s)
- Bianca Berto
- School of Biological Sciences The University of Western Australia Crawley Western Australia 6009 Australia
- Department of Biodiversity, Conservation and Attractions Kings Park Science Kings Park Western Australia 6005 Australia
| | - Alison L. Ritchie
- School of Biological Sciences The University of Western Australia Crawley Western Australia 6009 Australia
- Department of Biodiversity, Conservation and Attractions Kings Park Science Kings Park Western Australia 6005 Australia
| | - Todd E. Erickson
- School of Biological Sciences The University of Western Australia Crawley Western Australia 6009 Australia
- Department of Biodiversity, Conservation and Attractions Kings Park Science Kings Park Western Australia 6005 Australia
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10
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Pedrini S, Balestrazzi A, Madsen MD, Bhalsing K, Hardegree SP, Dixon KW, Kildisheva OA. Seed enhancement: getting seeds restoration‐ready. Restor Ecol 2020. [DOI: 10.1111/rec.13184] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Simone Pedrini
- ARC‐Centre for Mine Site Restoration, Department of Environment and AgricultureCurtin University Kent Street Bentley 6102 Australia
| | - Alma Balestrazzi
- Department of Biology and Biotechnology ‘L. Spallanzani’University of Pavia via Ferrata 1 27100 Pavia Italy
| | - Matthew D. Madsen
- Department of Plant and Wildlife SciencesBrigham Young University Provo UT 84602 U.S.A
| | - Khiraj Bhalsing
- ARC‐Centre for Mine Site Restoration, Department of Environment and AgricultureCurtin University Kent Street Bentley 6102 Australia
| | | | - Kingsley W. Dixon
- ARC‐Centre for Mine Site Restoration, Department of Environment and AgricultureCurtin University Kent Street Bentley 6102 Australia
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11
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Gianella M, Balestrazzi A, Pagano A, Müller JV, Kyratzis AC, Kikodze D, Canella M, Mondoni A, Rossi G, Guzzon F. Heteromorphic seeds of wheat wild relatives show germination niche differentiation. Plant Biol (Stuttg) 2020; 22:191-202. [PMID: 31639249 DOI: 10.1111/plb.13060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/12/2019] [Indexed: 05/12/2023]
Abstract
Crop wild relatives are fundamental genetic resources for crop improvement. Wheat wild relatives often produce heteromorphic seeds that differ in morphological and physiological traits. Several Aegilops and Triticum species possess, within the same spikelet, a dimorphic seed pair, with one seed being larger than the other. A comprehensive analysis is needed to understand which traits are involved in seed dimorphism and if these aspects of variation in dimorphic pairs are functionally related. To this end, dispersal units of Triticum urartu and five Aegilops species were X-rayed and the different seed morphs weighed. Germination tests were carried out on seeds, both dehulled and left in their dispersal units. Controlled ageing tests were performed to detect differences in seed longevity among seed morphs, and the antioxidant profile was assessed in terms of antioxidant compounds equipment and expression of selected antioxidant genes. We used PCA to group seed morphs sharing similar patterns of germination traits, longevity estimates and antioxidant profile. Different seed morphs differed significantly in terms of mass, final germination, germination timing, longevity estimates and antioxidant profile in most of the tested species. Small seeds germinated slower, had lower germination when left in their dispersal units, a higher antioxidant potential and were longer-lived than large seeds. The antioxidant gene expression varied between morphs, with different patterns across species but not clearly reflecting the phenotypic observations. The results highlight different trait trade-offs in dimorphic seeds of Aegilops and T. urartu, affecting their germination phenology and longevity, thereby resulting in recruitment niche differentiation.
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Affiliation(s)
- M Gianella
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - A Balestrazzi
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - A Pagano
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
| | - J V Müller
- Millennium Seed Bank, Conservation Science Department, Royal Botanic Gardens Kew, Wakehurst Place, UK
| | - A C Kyratzis
- Vegetable Crops Sector, Agricultural Research Institute of Cyprus, Nicosia, Cyprus
| | - D Kikodze
- Institute of Botany, Ilia State University, Tbilisi, Georgia
| | - M Canella
- Department of Earth and Environmental Sciences, University of Pavia, Pavia, Italy
| | - A Mondoni
- Department of Earth and Environmental Sciences, University of Pavia, Pavia, Italy
| | - G Rossi
- Department of Earth and Environmental Sciences, University of Pavia, Pavia, Italy
| | - F Guzzon
- International Maize and Wheat Improvement Center (CIMMYT), Texcoco, Estado de Mexico, Mexico
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12
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Duncan C, Schultz NL, Good MK, Lewandrowski W, Cook S. The risk-takers and -avoiders: germination sensitivity to water stress in an arid zone with unpredictable rainfall. AoB Plants 2019; 11:plz066. [PMID: 31777652 PMCID: PMC6863470 DOI: 10.1093/aobpla/plz066] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 10/03/2019] [Indexed: 05/28/2023]
Abstract
Water availability is a critical driver of population dynamics in arid zones, and plant recruitment is typically episodic in response to rainfall. Understanding species' germination thresholds is key for conservation and restoration initiatives. Thus, we investigated the role of water availability in the germination traits of keystone species in an arid ecosystem with stochastic rainfall. We measured seed germination responses of five arid species, along gradients of temperature and water potential under controlled laboratory conditions. We then identified the cardinal temperatures and base water potentials for seed germination, and applied the hydrotime model to assess germination responses to water stress. Optimum temperatures for germination ranged from 15 to 31 °C under saturated conditions (0 MPa), and three species had low minimum temperatures for germination (<3 °C). A small proportion of seeds of all species germinated under dry conditions (Ψ ≤ -1 MPa), although base water potential for germination (Ψ b50) ranged from -0.61 to -0.79 MPa. Species adhered to one of two germination traits: (i) the risk-takers which require less moisture availability for germination, and which can germinate over a wider range of temperatures irrespective of water availability (Casuarina pauper and Maireana pyramidata), and (ii) the risk-avoiders which have greater moisture requirements, a preference for cold climate germination, and narrower temperature ranges for germination when water availability is low (Atriplex rhagodioides, Maireana sedifolia and Hakea leucoptera). High seed longevity under physiological stress in H. leucoptera, combined with a risk-avoiding strategy, allows bet-hedging. The hydrotime model predicted lower base water potentials for germination than observed by the data, further supporting our assertion that these species have particular adaptations to avoid germination during drought. This study provides insights into the complex physiological responses of seeds to environmental stress, and relates seed germination traits to community dynamics and restoration in arid zones.
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Affiliation(s)
- Corrine Duncan
- School of Health and Life Sciences, Federation University, Mt Helen, VIC, Australia
| | - Nick L Schultz
- School of Health and Life Sciences, Federation University, Mt Helen, VIC, Australia
| | - Megan K Good
- BioSciences, University of Melbourne, Parkville, VIC, Australia
| | - Wolfgang Lewandrowski
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Simon Cook
- School of Health and Life Sciences, Federation University, Mt Helen, VIC, Australia
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13
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Duncan C, Schultz N, Lewandrowski W, Good MK, Cook S. Lower dormancy with rapid germination is an important strategy for seeds in an arid zone with unpredictable rainfall. PLoS One 2019; 14:e0218421. [PMID: 31504045 PMCID: PMC6736279 DOI: 10.1371/journal.pone.0218421] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/27/2019] [Indexed: 11/24/2022] Open
Abstract
Seed germination traits are key drivers of population dynamics, yet they are under-represented in community ecology studies, which have predominately focussed on adult plant and seed morphological traits. We studied the seed traits and germination strategy of eight woody plant species to investigate regeneration strategies in the arid zone of eastern Australia. To cope with stochastic and minimal rainfall, we predict that arid seeds will either have rapid germination across a wide range of temperatures, improved germination under cooler temperatures, or dormancy and/or longevity traits to delay or stagger germination across time. To understand how temperature affects germination responses, seeds of eight keystone arid species were germinated under laboratory conditions, and under three diurnal temperatures (30/20°C, 25/15°C and 17/7°C) for 30 days. We also tested for decline in seed viability across 24 months in a dry-aging treatment (~20°C). Six of the eight arid species studied had non-dormant, rapidly germinating seeds, and only two species had physiological dormancy traits. Seed longevity differed widely between species, from one recalcitrant species surviving only months in aging (P50 = <3 months) and one serotinous species surviving for many years (P50 = 84 months). Our results highlight the importance of understanding the reproductive strategies of plant species in arid environments. Rapid germination, the dominant seed trait of species included in this study, allows arid species to capitalise on sporadic rainfall. However, some species also exhibit dormancy and delayed germination; this an alternative strategy which spreads the risk of germination failure over time.
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Affiliation(s)
- Corrine Duncan
- School of Health and Life Sciences, Federation University, Mt Helen, VIC, Australia
- * E-mail:
| | - Nick Schultz
- School of Health and Life Sciences, Federation University, Mt Helen, VIC, Australia
| | - Wolfgang Lewandrowski
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Megan K. Good
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Simon Cook
- School of Health and Life Sciences, Federation University, Mt Helen, VIC, Australia
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14
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Ma H, Erickson TE, Merritt DJ. Seed dormancy regulates germination response to smoke and temperature in a rhizomatous evergreen perennial. AoB Plants 2018; 10:ply042. [PMID: 30057736 PMCID: PMC6057524 DOI: 10.1093/aobpla/ply042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
Seed dormancy status regulates the response of seeds to environmental cues that can trigger germination. Anigozanthos flavidus (Haemodoraceae) produces seeds with morphophysiological dormancy (MPD) that are known to germinate in response to smoke, but embryo growth dynamics and germination traits in response to temperatures and after-ripening have not been well characterized. Seeds of A. flavidus, after-ripened for 28 months at 15 °C/15 % relative humidity, were incubated on water agar, water agar containing 1 μM karrikinolide (KAR1) or 50 μM glyceronitrile at 5, 10, 15, 20, 25, 20/10 and 25/15 °C for 28 days. After incubation at 5, 10 and 25 °C for 28 days, seeds were transferred to 15 °C for another 28 days. Embryo growth dynamics were tested at 5, 10, 15 and 25 °C. Results demonstrated that fresh seeds of A. flavidus had MPD and the physiological dormancy (PD) component could be broken by either glyceronitrile or dry after-ripening. After-ripened seeds germinated to ≥80 % at 15-20 °C while no additional benefit of germination was observed in the presence of the KAR1 or glyceronitrile. Embryo length significantly increased at 10 °C, and only slightly increased at 5 °C, while growth did not occur at 25 °C. When un-germinated seeds were moved from 5-10 °C to 15 °C for a further 28 days, germination increased from 0 to >80 % in significantly less time indicating that cold stratification may play a key role in the germination process during winter and early spring in A. flavidus. The lower germination (<50 %) of seeds moved from 25 to 15 °C was produced by the induction of secondary dormancy. Induction of secondary dormancy in seeds exposed to warm stratification, a first report for Anigozanthos species, suggests that cycling of PD may be an important mechanism of controlling germination timing in the field.
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Affiliation(s)
- Hongyuan Ma
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Shengbei Street, Changchun, Jilin, China
| | - Todd E Erickson
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Fraser Avenue, Kings Park, Western Australia, Australia
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, Australia
| | - David J Merritt
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Fraser Avenue, Kings Park, Western Australia, Australia
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, Australia
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