The risk-takers and -avoiders: germination sensitivity to water stress in an arid zone with unpredictable rainfall
| Autor: | Megan K. Good, Nick L. Schultz, Wolfgang Lewandrowski, Corrine Duncan, Simon Cook |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
cardinal temperatures Population ved/biology.organism_classification_rank.species Plant Science Biology 010603 evolutionary biology 01 natural sciences Studies t 50 Maireana sedifolia water potential bet-hedging education Hakea leucoptera seed physiology education.field_of_study Moisture ved/biology hydrotime biology.organism_classification seed mass Arid Agronomy Germination Soil water Ψ b50 Annual plant 010606 plant biology & botany |
| Zdroj: | AoB Plants |
| ISSN: | 2041-2851 |
| DOI: | 10.1093/aobpla/plz066 |
| Popis: | 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 ( In an arid ecosystem with unpredictable rainfall, we investigated the germination traits of keystone trees and shrubs. Species adhered to one of two germination strategies: (i) the risk-takers which require less moisture availability for germination and have wide temperature ranges for germination (Casuarina pauper and Maireana pyramidata), and (ii) the risk-avoiders that have greater moisture requirements, a preference for cold climate germination, and narrower temperature ranges for germination (Atriplex rhagodioides, Maireana sedifolia and Hakea leucoptera). We suggest that these species have particular adaptations to avoid germination during drought, and this is supported by low base water potentials for germination. |
| Databáze: | OpenAIRE |
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