Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis)
Trees are suffering mortality across the globe as a result of drought, warming, and biotic attacks. The combined effects of warming and drought on in situ tree chemical defenses against herbivory have not been studied to date. To address this, we transplanted mature piñon pine trees—a well-studied s...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2019-01-01
|
| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ab1493 |
| _version_ | 1827870637847216128 |
|---|---|
| author | Amy M Trowbridge Paul C Stoy Henry D Adams Darin J Law David D Breshears Detlev Helmig Russell K Monson |
| author_facet | Amy M Trowbridge Paul C Stoy Henry D Adams Darin J Law David D Breshears Detlev Helmig Russell K Monson |
| author_sort | Amy M Trowbridge |
| collection | DOAJ |
| description | Trees are suffering mortality across the globe as a result of drought, warming, and biotic attacks. The combined effects of warming and drought on in situ tree chemical defenses against herbivory have not been studied to date. To address this, we transplanted mature piñon pine trees—a well-studied species that has undergone extensive drought and herbivore-related mortality—within their native woodland habitat and also to a hotter-drier habitat and measured monoterpene emissions and concentrations across the growing season. We hypothesized that greater needle temperatures in the hotter-drier site would increase monoterpene emission rates and consequently lower needle monoterpene concentrations, and that this temperature effect would dominate the seasonal pattern of monoterpene concentrations regardless of drought. In support of our hypothesis, needle monoterpene concentrations were lower across all seasons in trees transplanted to the hotter-drier site. Contrary to our hypothesis, basal emission rates (emission rates normalized to 30 °C and a radiative flux of 1000 μ mol m ^−2 s ^−1 ) did not differ between sites. This is because an increase in emissions at the hotter-drier site from a 1.5 °C average temperature increase was offset by decreased emissions from greater plant water stress. High emission rates were frequently observed during June, which were not related to plant physiological or environmental factors but did not occur below pre-dawn leaf water potentials of −2 MPa, the approximate zero carbon assimilation point in piñon pine. Emission rates were also not under environmental or plant physiological control when pre-dawn leaf water potential was less than −2 MPa. Our results suggest that drought may override the effects of temperature on monoterpene emissions and tissue concentrations, and that the influence of drought may occur through metabolic processes sensitive to the overall needle carbon balance. |
| first_indexed | 2024-03-12T16:00:06Z |
| format | Article |
| id | doaj.art-e6742752fb514e5388ebf2fb52a52ab1 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:00:06Z |
| publishDate | 2019-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-e6742752fb514e5388ebf2fb52a52ab12023-08-09T14:42:50ZengIOP PublishingEnvironmental Research Letters1748-93262019-01-0114606500610.1088/1748-9326/ab1493Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis)Amy M Trowbridge0https://orcid.org/0000-0001-8993-2530Paul C Stoy1https://orcid.org/0000-0002-6053-6232Henry D Adams2https://orcid.org/0000-0001-9630-4305Darin J Law3https://orcid.org/0000-0002-0903-4210David D Breshears4https://orcid.org/0000-0001-6601-0058Detlev Helmig5https://orcid.org/0000-0003-1612-1651Russell K Monson6Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, United States of AmericaDepartment of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, United States of AmericaDepartment of Plant Biology, Ecology, and Evolution, Oklahoma State University , Stillwater, OK 74078, United States of AmericaSchool of Natural Resources and the Environment, University of Arizona , Tucson, AZ 85721, United States of AmericaSchool of Natural Resources and the Environment, University of Arizona , Tucson, AZ 85721, United States of America; Department of Ecology and Evolutionary Biology, University of Arizona , Tucson, AZ 85721, United States of AmericaInstitute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, United States of AmericaDepartment of Ecology and Evolutionary Biology, University of Arizona , Tucson, AZ 85721, United States of America; Laboratory for Tree Ring Research, University of Arizona , Tucson, AZ 85721, United States of AmericaTrees are suffering mortality across the globe as a result of drought, warming, and biotic attacks. The combined effects of warming and drought on in situ tree chemical defenses against herbivory have not been studied to date. To address this, we transplanted mature piñon pine trees—a well-studied species that has undergone extensive drought and herbivore-related mortality—within their native woodland habitat and also to a hotter-drier habitat and measured monoterpene emissions and concentrations across the growing season. We hypothesized that greater needle temperatures in the hotter-drier site would increase monoterpene emission rates and consequently lower needle monoterpene concentrations, and that this temperature effect would dominate the seasonal pattern of monoterpene concentrations regardless of drought. In support of our hypothesis, needle monoterpene concentrations were lower across all seasons in trees transplanted to the hotter-drier site. Contrary to our hypothesis, basal emission rates (emission rates normalized to 30 °C and a radiative flux of 1000 μ mol m ^−2 s ^−1 ) did not differ between sites. This is because an increase in emissions at the hotter-drier site from a 1.5 °C average temperature increase was offset by decreased emissions from greater plant water stress. High emission rates were frequently observed during June, which were not related to plant physiological or environmental factors but did not occur below pre-dawn leaf water potentials of −2 MPa, the approximate zero carbon assimilation point in piñon pine. Emission rates were also not under environmental or plant physiological control when pre-dawn leaf water potential was less than −2 MPa. Our results suggest that drought may override the effects of temperature on monoterpene emissions and tissue concentrations, and that the influence of drought may occur through metabolic processes sensitive to the overall needle carbon balance.https://doi.org/10.1088/1748-9326/ab1493droughtheat stressmonoterpenesPinus edulisplant defensesecondary metabolites |
| spellingShingle | Amy M Trowbridge Paul C Stoy Henry D Adams Darin J Law David D Breshears Detlev Helmig Russell K Monson Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis) Environmental Research Letters drought heat stress monoterpenes Pinus edulis plant defense secondary metabolites |
| title | Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis) |
| title_full | Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis) |
| title_fullStr | Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis) |
| title_full_unstemmed | Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis) |
| title_short | Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis) |
| title_sort | drought supersedes warming in determining volatile and tissue defenses of pinon pine pinus edulis |
| topic | drought heat stress monoterpenes Pinus edulis plant defense secondary metabolites |
| url | https://doi.org/10.1088/1748-9326/ab1493 |
| work_keys_str_mv | AT amymtrowbridge droughtsupersedeswarmingindeterminingvolatileandtissuedefensesofpinonpinepinusedulis AT paulcstoy droughtsupersedeswarmingindeterminingvolatileandtissuedefensesofpinonpinepinusedulis AT henrydadams droughtsupersedeswarmingindeterminingvolatileandtissuedefensesofpinonpinepinusedulis AT darinjlaw droughtsupersedeswarmingindeterminingvolatileandtissuedefensesofpinonpinepinusedulis AT daviddbreshears droughtsupersedeswarmingindeterminingvolatileandtissuedefensesofpinonpinepinusedulis AT detlevhelmig droughtsupersedeswarmingindeterminingvolatileandtissuedefensesofpinonpinepinusedulis AT russellkmonson droughtsupersedeswarmingindeterminingvolatileandtissuedefensesofpinonpinepinusedulis |