title: Demonstration of a diel trend in sensitivity of Gossypium to ozone: a step toward relating O₃ injury to exposure or flux.
abstract: Plant injury by ozone (O3) occurs in three stages, O3 entrance through stomata, overcoming defences, and attack on bioreceptors. Concentration, deposition, and uptake of O3 are accessible by observation and modelling, while injury can be assessed visually or through remote sensing. However, the relationship between O3 metrics and injury is confounded by variation in sensitivity to O3. Sensitivity weighting parameters have previously been assigned to different plant functional types and growth stages, or by differentially weighting O3 concentrations, but diel and seasonal variability have not been addressed. Here a plant sensitivity parameter (S) is introduced, relating injury to O3 dose (uptake) using three independent injury endpoints in the crop species, Pima cotton (Gossypium barbadense). The diel variability of S was determined by assessment at 2h intervals. Pulses of O3 (15 min) were used to assess passive (constitutive) defence mechanisms and dose was used rather than concentration to avoid genetic or environmental effects on stomatal regulation. A clear diel trend in S was apparent, with maximal sensitivity in mid-afternoon, not closely related to gas exchange, whole leaf ascorbate, or total antioxidant capacity. This physiologically based sensitivity parameter provides a novel weighting factor to improve modelled relationships between either flux or exposure to O3, and O3 impacts. This represents a substantial improvement over concentration- or phenology-based weighting factors currently in use. Future research will be required to characterize the variability and metabolic drivers of diel changes in S, and the performance of this parameter in prediction of O3 injury.
authors: Department of Botany and Plant Sciences, University of California at Riverside, 9240 South Riverbend Ave., Parlier, CA 93648, USA. dagrantz@ucanr.edu
authors: D A
authors: DA
authors: Grantz
authors: H-B
authors: HB
authors: Vu
authors: R L
authors: RL
authors: Heath
authors: K O
authors: KO
authors: Burkey
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D003368:Gossypium / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010126:Ozone / Q000378:metabolism* / Q000494:pharmacology; D010935:Plant Diseases; D018515:Plant Leaves / Q000378:metabolism; D054046:Plant Stomata / Q000378:metabolism / Q000502:physiology; D012621:Seasons; D013312:Stress, Physiological; D013997:Time Factors
chemical_list: D000975:Antioxidants; D002734:Chlorophyll; D010126:Ozone
references: Environ Pollut. 1988;53(1-4):43-62
references: 15092540
references: Nature. 2007 Aug 16;448(7155):791-4
references: 17653194
references: Environ Pollut. 2008 Jul;154(2):241-53
references: 18031879
references: Naturwissenschaften. 2009 Feb;96(2):173-94
references: 19020849
references: Biochem Biophys Res Commun. 2008 Feb 8;366(2):271-4
references: 18082136
references: Environ Pollut. 2000 Sep;109(3):403-13
references: 15092873
references: J Exp Bot. 2000 May;51(346):901-10
references: 10948216
references: J Exp Bot. 2012 Jun;63(11):4303-13
references: 22563119
references: J Integr Plant Biol. 2009 Apr;51(4):337-51
references: 21452584
references: Tree Physiol. 2010 Nov;30(11):1415-32
references: 21030406
references: Plant Cell Environ. 2010 Jun;33(6):914-25
references: 20082669
references: Sci Total Environ. 2006 Oct 15;370(1):117-32
references: 16846632
references: Environ Pollut. 1997;98(1):51-60
references: 15093344
references: Planta. 2007 Apr;225(5):1255-64
references: 17043889
references: Environ Pollut. 2008 Nov;156(1):11-5
references: 18243452
references: J Exp Bot. 2010 Mar;61(3):629-33
references: 19923198
references: Environ Pollut. 2010 Oct;158(10):3164-71
references: 20656389
references: Environ Pollut. 2003;125(1):99-110
references: 12804832
references: Plant Cell Environ. 2010 Sep;33(9):1569-81
references: 20444212
references: Plant Cell Environ. 2010 May;33(5):717-28
references: 20002655
references: Environ Pollut. 2007 Oct;149(3):336-47
references: 17618715
references: Plant Cell Environ. 2008 Sep;31(9):1237-49
references: 18518918
references: Planta. 2000 Feb;210(3):454-67
references: 10750904
references: J Exp Bot. 2010 Mar;61(5):1405-17
references: 20164144
references: New Phytol. 2007;174(1):7-9
references: 17335492
references: J Exp Bot. 2012 Jan;63(2):527-36
references: 22016429
references: Plant Cell Environ. 2012 Aug;35(8):1456-66
references: 22380512
references: Ann Bot. 2003 Jan;91 Spec No:179-94
references: 12509339
references: Tree Physiol. 2001 Mar;21(5):337-44
references: 11262925
references: Physiol Plant. 2001 Nov;113(3):377-383
references: 12060283
references: Environ Pollut. 2007 Dec;150(3):355-62
references: 17442469