干旱区生态环境知识资源中心(Arid): The risk-takers and -avoiders: germination sensitivity to water stress in an arid zone with unpredictable rainfall

Arid

DOI	10.1093/aobpla/plz066
	The risk-takers and -avoiders: germination sensitivity to water stress in an arid zone with unpredictable rainfall
	Duncan, Corrine 1; Schultz, Nick L.1; Good, Megan K.2; Lewandrowski, Wolfgang 3,4; Cook, Simon 1
通讯作者	Duncan, Corrine
来源期刊	AOB PLANTS
ISSN	2041-2851
出版年	2019
卷号	11 期号:6
英文摘要	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 degrees C under saturated conditions (0 MPa), and three species had low minimum temperatures for germination (<3 degrees C). A small proportion of seeds of all species germinated under dry conditions (Psi <= -1 MPa), although base water potential for germination (Psi(b)50) 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.
英文关键词	Psi(b)50 t(50) bet-hedging cardinal temperatures hydrotime seed mass seed physiology water potential
类型	Article
语种	英语
国家	Australia
开放获取类型	Green Published, gold
收录类别	SCI-E
WOS记录号	WOS:000510159100007
WOS关键词	HYDROTHERMAL TIME MODEL ; SEED-GERMINATION ; FUNCTIONAL TRAITS ; SOIL-MOISTURE ; ANNUAL PLANTS ; TEMPERATURE ; DESERT ; SIZE ; STRATEGIES ; EMERGENCE
WOS类目	Plant Sciences ; Ecology
WOS研究方向	Plant Sciences ; Environmental Sciences & Ecology
EI主题词	2019-12-01
来源机构	University of Western Australia
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/311129
作者单位	1.Federat Univ, Sch Hlth & Life Sci, Mt Helen, Vic 3350, Australia; 2.Univ Melbourne, BioSci, Parkville, Vic 3052, Australia; 3.Kings Pk Sci, Dept Biodivers Conservat & Attract, Kings Pk, WA 6005, Australia; 4.Univ Western Australia, Sch Biol Sci, Crawley, WA 6009, Australia
推荐引用方式 GB/T 7714	Duncan, Corrine,Schultz, Nick L.,Good, Megan K.,et al. The risk-takers and -avoiders: germination sensitivity to water stress in an arid zone with unpredictable rainfall[J]. University of Western Australia,2019,11(6).
APA	Duncan, Corrine,Schultz, Nick L.,Good, Megan K.,Lewandrowski, Wolfgang,&Cook, Simon.(2019).The risk-takers and -avoiders: germination sensitivity to water stress in an arid zone with unpredictable rainfall.AOB PLANTS,11(6).
MLA	Duncan, Corrine,et al."The risk-takers and -avoiders: germination sensitivity to water stress in an arid zone with unpredictable rainfall".AOB PLANTS 11.6(2019).