Lower dormancy with rapid germination is an important strategy for seeds in an arid zone with unpredictable rainfall
- Duncan, Corrine, Schultz, Nick, Lewandrowski, Wolfgang, Good, Megan, Cook, Simon
- Authors: Duncan, Corrine , Schultz, Nick , Lewandrowski, Wolfgang , Good, Megan , Cook, Simon
- Date: 2019
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 14, no. 9 (2019), p.
- Full Text:
- Reviewed:
- Description: 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 (
- Authors: Duncan, Corrine , Schultz, Nick , Lewandrowski, Wolfgang , Good, Megan , Cook, Simon
- Date: 2019
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 14, no. 9 (2019), p.
- Full Text:
- Reviewed:
- Description: 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 (
The risk-takers and -avoiders : germination sensitivity to water stress in an arid zone with unpredictable rainfall
- Duncan, Corrine, Schultz, Nick, Good, Megan, Lewandrowski, Wolfgang, Cook, Simon
- Authors: Duncan, Corrine , Schultz, Nick , Good, Megan , Lewandrowski, Wolfgang , Cook, Simon
- Date: 2019
- Type: Text , Journal article
- Relation: AoB PLANTS Vol. 11, no. 6 (2019), p.
- Full Text:
- Reviewed:
- Description: 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 (ψb50) 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. © 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company.
- Authors: Duncan, Corrine , Schultz, Nick , Good, Megan , Lewandrowski, Wolfgang , Cook, Simon
- Date: 2019
- Type: Text , Journal article
- Relation: AoB PLANTS Vol. 11, no. 6 (2019), p.
- Full Text:
- Reviewed:
- Description: 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 (ψb50) 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. © 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company.
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