title: Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest.
abstract: Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C₅ and C₆ GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C₆ GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.
authors.affiliation: Climate Science Department, Earth Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd, building 74, Berkeley, CA 94720, USA. kjjardine@lbl.gov.
authors.forename: Kolby J
authors.initials: KJ
authors.lastname: Jardine
authors.affiliation: Climate Science Department, Earth Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd, building 74, Berkeley, CA 94720, USA. clafontes@gmail.com.|Department of Geography, University of California Berkeley, 507 McCone Hall #4740, Berkeley, CA 94720, USA. clafontes@gmail.com.
authors.forename: Jeffrey Q
authors.initials: JQ
authors.lastname: Chambers
authors.affiliation: Climate Science Department, Earth Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd, building 74, Berkeley, CA 94720, USA. jaholm@lbl.gov.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Holm
authors.affiliation: National Institute for Amazon Research (INPA), Ave. Andre Araujo 2936, Campus II, Building LBA, Manaus, AM 69.080-97, Brazil. angela.jardine@inpa.gov.br.
authors.forename: Angela B
authors.initials: AB
authors.lastname: Jardine
authors.affiliation: Department of Geography, University of California Berkeley, 507 McCone Hall #4740, Berkeley, CA 94720, USA. clafontes@gmail.com.
authors.forename: Clarissa G
authors.initials: CG
authors.lastname: Fontes
authors.affiliation: National Institute for Amazon Research (INPA), Ave. Andre Araujo 2936, Campus II, Building LBA, Manaus, AM 69.080-97, Brazil. lotraquelu@gmail.com.
authors.forename: Raquel F
authors.initials: RF
authors.lastname: Zorzanelli
authors.affiliation: Department of Neurobiology, The Barrow Neurological Institute, Saint Joseph's Hospital and Medical Center, 350 W Thomas Rd, Phoenix, AZ 85013, USA. kmeyers1@email.arizona.edu.
authors.forename: Kimberly T
authors.initials: KT
authors.lastname: Meyers
authors.affiliation: National Institute for Amazon Research (INPA), Ave. Andre Araujo 2936, Campus II, Building LBA, Manaus, AM 69.080-97, Brazil. viniciusfernandes11@yahoo.com.br.
authors.forename: Vinicius Fernadez
authors.initials: VF
authors.lastname: de Souza
authors.affiliation: National Institute for Amazon Research (INPA), Ave. Andre Araujo 2936, Campus II, Building LBA, Manaus, AM 69.080-97, Brazil. sabrinagarcia.sg@gmail.com.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Garcia
authors.affiliation: National Institute for Amazon Research (INPA), Ave. Andre Araujo 2936, Campus II, Building LBA, Manaus, AM 69.080-97, Brazil. bruno.oliva.gimenez@gmail.com.
authors.forename: Bruno O
authors.initials: BO
authors.lastname: Gimenez
authors.affiliation: National Institute for Amazon Research (INPA), Ave. Andre Araujo 2936, Campus II, Building LBA, Manaus, AM 69.080-97, Brazil. luanipiva@yahoo.com.br.
authors.forename: Luani R de O
authors.initials: LR
authors.lastname: Piva
authors.affiliation: National Institute for Amazon Research (INPA), Ave. Andre Araujo 2936, Campus II, Building LBA, Manaus, AM 69.080-97, Brazil. niro@inpa.gov.br.
authors.forename: Niro
authors.initials: N
authors.lastname: Higuchi
authors.affiliation: Instituto de Fisica, Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 Sao Paulo SP 05508-900, Brazil. artaxo@if.usp.br.
authors.forename: Paulo
authors.initials: P
authors.lastname: Artaxo
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. smartin@seas.harvard.edu.|Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA. smartin@seas.harvard.edu.
authors.forename: Scot
authors.initials: S
authors.lastname: Martin
authors.affiliation: National Institute for Amazon Research (INPA), Ave. Andre Araujo 2936, Campus II, Building LBA, Manaus, AM 69.080-97, Brazil. aomanzi@gmail.com.
authors.forename: Antônio O
authors.initials: AO
authors.lastname: Manzi
keywords: abiotic stress; drought; green leaf volatiles; leaf temperatures; tree mortality