干旱区生态环境知识资源中心(Arid): First-year Acacia seedlings are anisohydric water-spenders but differ in their rates of water use

Arid

DOI	10.1002/ajb2.16032
	First-year Acacia seedlings are anisohydric water-spenders but differ in their rates of water use
	Cory, Scott T.; Smith, William K.; Anderson, T. Michael
通讯作者	Cory, ST
来源期刊	AMERICAN JOURNAL OF BOTANY
ISSN	0002-9122
EISSN	1537-2197
出版年	2022
卷号	109 期号:8 页码:1251-1261
英文摘要	Premise First-year seedlings (FYS) of tree species may be a critical demographic bottleneck in semi-arid, seasonally dry ecosystems such as savannas. Given the highly variable water availability and potentially strong FYS-grass competition for water, FYS water-use strategies may play a crucial role in FYS establishment in savannas and, ultimately, in tree-grass competition and coexistence. Methods We examined drought responses in FYS of two tree species that are dominant on opposite ends of an aridity gradient in Serengeti, Acacia (=Vachellia) tortilis and A. robusta. In a glasshouse experiment, gas exchange and whole-plant hydraulic conductance (K-plant) were measured as soil water potential (psi(soil)) declined. Trajectory of the psi(leaf)/psi(soil) relationship during drought elucidated the degree of iso/anisohydry. Results Both species were strongly anisohydric water-spenders, allowing rapid wet-season C gain after pulses of moisture availability. Despite being equally vulnerable to declines in K-plant under severe drought, they differed in their rates of water use. Acacia tortilis, which occurs in the more arid regions, initially had greater K-max, transpiration (E), and photosynthesis (A(net)) than A. robusta. Conclusions This work demonstrates an important mechanism of FYS establishment in savannas: Rather than investing in drought tolerance, savanna FYS maximize gas exchange during wet periods at the expense of desiccation during dry seasons. FYS establishment appears dependent on high C uptake during the pulses of water availability that characterize habitats dominated by these species. This study increases our understanding of species-scale plant ecophysiology and ecosystem-scale patterns of tree-grass coexistence.
英文关键词	Acacia drought first-year seedling hydraulic conductance hydraulic vulnerability iso anisohydry continuum savanna Serengeti tree-grass competition Vachellia
类型	Article
语种	英语
开放获取类型	hybrid, Green Published
收录类别	SCI-E
WOS记录号	WOS:000839465600001
WOS关键词	XYLEM VULNERABILITY ; TREE SEEDLINGS ; SAVANNA TREES ; C-4 GRASSES ; WOODY COVER ; FIRE ; DROUGHT ; MORTALITY ; SURVIVAL ; RAINFALL
WOS类目	Plant Sciences
WOS研究方向	Plant Sciences
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/391809
推荐引用方式 GB/T 7714	Cory, Scott T.,Smith, William K.,Anderson, T. Michael. First-year Acacia seedlings are anisohydric water-spenders but differ in their rates of water use[J],2022,109(8):1251-1261.
APA	Cory, Scott T.,Smith, William K.,&Anderson, T. Michael.(2022).First-year Acacia seedlings are anisohydric water-spenders but differ in their rates of water use.AMERICAN JOURNAL OF BOTANY,109(8),1251-1261.
MLA	Cory, Scott T.,et al."First-year Acacia seedlings are anisohydric water-spenders but differ in their rates of water use".AMERICAN JOURNAL OF BOTANY 109.8(2022):1251-1261.