Seawater exposure causes hydraulic damage in dying Sitka-spruce trees

Hongxia Zhang; Xinrong Li; Wenzhi Wang; Alexandria L Pivovaroff; Weibin Li; Peipei Zhang; Nicholas D Ward; Allison Myers-Pigg; Henry D Adams; Riley Leff; Anzhi Wang; Fenghui Yuan; Jiabing Wu; Steve Yabusaki; Scott Waichler; Vanessa L Bailey; Dexin Guan; Nate G McDowell

doi:10.1093/plphys/kiab295

Seawater exposure causes hydraulic damage in dying Sitka-spruce trees

Plant Physiol. 2021 Oct 5;187(2):873-885. doi: 10.1093/plphys/kiab295.

Authors

Hongxia Zhang^{1

2

3}, Xinrong Li¹, Wenzhi Wang^{3

4}, Alexandria L Pivovaroff³, Weibin Li^{3

5}, Peipei Zhang³, Nicholas D Ward^{6

7}, Allison Myers-Pigg⁵, Henry D Adams⁸, Riley Leff³, Anzhi Wang², Fenghui Yuan², Jiabing Wu², Steve Yabusaki⁹, Scott Waichler⁹, Vanessa L Bailey¹⁰, Dexin Guan², Nate G McDowell^{3

11}

Affiliations

¹ Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
² Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
³ Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
⁴ The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China.
⁵ State Key Laboratory of Grassland and Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China.
⁶ Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim, Washington 98382, USA.
⁷ School of Oceanography, University of Washington, Seattle, Washington 98195, USA.
⁸ School of the Environment, Washington State University, Pullman, Washington 99164-2812, USA.
⁹ Earth Systems Science, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
¹⁰ Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
¹¹ School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA.

Abstract

Sea-level rise is one of the most critical challenges facing coastal ecosystems under climate change. Observations of elevated tree mortality in global coastal forests are increasing, but important knowledge gaps persist concerning the mechanism of salinity stress-induced nonhalophytic tree mortality. We monitored progressive mortality and associated gas exchange and hydraulic shifts in Sitka-spruce (Picea sitchensis) trees located within a salinity gradient under an ecosystem-scale change of seawater exposure in Washington State, USA. Percentage of live foliated crown (PLFC) decreased and tree mortality increased with increasing soil salinity during the study period. A strong reduction in gas exchange and xylem hydraulic conductivity (Ks) occurred during tree death, with an increase in the percentage loss of conductivity (PLC) and turgor loss point (πtlp). Hydraulic and osmotic shifts reflected that hydraulic function declined from seawater exposure, and dying trees were unable to support osmotic adjustment. Constrained gas exchange was strongly related to hydraulic damage at both stem and leaf levels. Significant correlations between foliar sodium (Na+) concentration and gas exchange and key hydraulic parameters (Ks, PLC, and πtlp) suggest that cellular injury related to the toxic effects of ion accumulation impacted the physiology of these dying trees. This study provides evidence of toxic effects on the cellular function that manifests in all aspects of plant functioning, leading to unfavourable osmotic and hydraulic conditions.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Climate Change*
Picea / physiology*
Salt Stress*
Seawater / adverse effects*
Trees / physiology*
Washington
Xylem / drug effects*
Xylem / physiology