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Title: Low Vulnerability to Xylem Embolism in Leaves and Stems of North American Oaks

Abstract

Although recent findings suggest that xylem embolism represents a significant, drought-induced damaging process in land plants, substantial debate surrounds the capacity of long-vesseled, ring-porous species to resist embolism. We investigated whether recent methodological developments could help resolve this controversy within Quercus, a long-vesseled, ring-porous temperate angiosperm genus, and shed further light on the importance of xylem vulnerability to embolism as an indicator of drought tolerance. We used the optical technique to quantify leaf and stem xylem vulnerability to embolism of eight Quercus species from the Mediterranean-type climate region of California to examine absolute measures of resistance to embolism as well as any potential hydraulic segmentation between tissue types. We demonstrated that our optical assessment reflected flow impairment for a subset of our sample species by quantifying changes in leaf hydraulic conductance in dehydrating branches. Air-entry water potential varied 2-fold in leaves, ranging from -1.7 ± 0.25 MPa to -3.74 ± 0.23 MPa, and 4-fold in stems, ranging from -1.17 ± 0.04 MPa to -4.91 ± 0.3 MPa. Embolism occurred earlier in leaves than in stems in only one out of eight sample species, and plants always lost turgor before experiencing stem embolism. Our results show that long-vesseled North American Quercusmore » species are more resistant to embolism than previously thought and support the hypothesis that avoiding stem embolism is a critical component of drought tolerance in woody trees. Accurately quantifying xylem vulnerability to embolism is essential for understanding species distributions along aridity gradients and predicting plant mortality during drought.« less

Authors:
ORCiD logo; ; ORCiD logo; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1480787
DOE Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Plant Physiology (Bethesda)
Additional Journal Information:
Journal Volume: 177; Journal Issue: 3; Journal ID: ISSN 0032-0889
Publisher:
American Society of Plant Biologists
Country of Publication:
United States
Language:
English

Citation Formats

Skelton, Robert Paul, Dawson, Todd E., Thompson, Sally E., Shen, Yuzheng, Weitz, Andrew P., and Ackerly, David. Low Vulnerability to Xylem Embolism in Leaves and Stems of North American Oaks. United States: N. p., 2018. Web. doi:10.1104/pp.18.00103.
Skelton, Robert Paul, Dawson, Todd E., Thompson, Sally E., Shen, Yuzheng, Weitz, Andrew P., & Ackerly, David. Low Vulnerability to Xylem Embolism in Leaves and Stems of North American Oaks. United States. doi:10.1104/pp.18.00103.
Skelton, Robert Paul, Dawson, Todd E., Thompson, Sally E., Shen, Yuzheng, Weitz, Andrew P., and Ackerly, David. Tue . "Low Vulnerability to Xylem Embolism in Leaves and Stems of North American Oaks". United States. doi:10.1104/pp.18.00103.
@article{osti_1480787,
title = {Low Vulnerability to Xylem Embolism in Leaves and Stems of North American Oaks},
author = {Skelton, Robert Paul and Dawson, Todd E. and Thompson, Sally E. and Shen, Yuzheng and Weitz, Andrew P. and Ackerly, David},
abstractNote = {Although recent findings suggest that xylem embolism represents a significant, drought-induced damaging process in land plants, substantial debate surrounds the capacity of long-vesseled, ring-porous species to resist embolism. We investigated whether recent methodological developments could help resolve this controversy within Quercus, a long-vesseled, ring-porous temperate angiosperm genus, and shed further light on the importance of xylem vulnerability to embolism as an indicator of drought tolerance. We used the optical technique to quantify leaf and stem xylem vulnerability to embolism of eight Quercus species from the Mediterranean-type climate region of California to examine absolute measures of resistance to embolism as well as any potential hydraulic segmentation between tissue types. We demonstrated that our optical assessment reflected flow impairment for a subset of our sample species by quantifying changes in leaf hydraulic conductance in dehydrating branches. Air-entry water potential varied 2-fold in leaves, ranging from -1.7 ± 0.25 MPa to -3.74 ± 0.23 MPa, and 4-fold in stems, ranging from -1.17 ± 0.04 MPa to -4.91 ± 0.3 MPa. Embolism occurred earlier in leaves than in stems in only one out of eight sample species, and plants always lost turgor before experiencing stem embolism. Our results show that long-vesseled North American Quercus species are more resistant to embolism than previously thought and support the hypothesis that avoiding stem embolism is a critical component of drought tolerance in woody trees. Accurately quantifying xylem vulnerability to embolism is essential for understanding species distributions along aridity gradients and predicting plant mortality during drought.},
doi = {10.1104/pp.18.00103},
journal = {Plant Physiology (Bethesda)},
issn = {0032-0889},
number = 3,
volume = 177,
place = {United States},
year = {2018},
month = {5}
}