title: Augmentation of abscisic acid (ABA) levels by drought does not induce short-term stomatal sensitivity to CO2 in two divergent conifer species.
abstract: The stomata of conifers display very little short-term response to changes in atmospheric CO(2) concentration (C(a)), whereas the stomatal responses of angiosperms to C(a) increase in response to water stress. This behaviour of angiosperm stomata appears to be dependent on foliar levels of abscisic acid (ABA(f)). Here two alternative explanations for the stomatal insensitivity of conifers to C(a) are tested: that conifers have either low ABA(f) or a higher or absent threshold for ABA-induced sensitivity. The responsiveness of stomatal conductance (g(s)) to a sequence of transitions in C(a) (386, 100, and 600 μmol mol(-1)) was recorded over a range of ABA(f) in an angiosperm and two divergent conifer species. The different ABA levels were induced by a mild drought cycle. Although the angiosperm and conifer species showed similar proportional increases in ABA(f) following drought, conifer stomata remained insensitive to changes in C(a) whereas angiosperm stomata showed enhanced sensitivity with increasing ABA(f). The conifers, however, had much higher ABA(f) prior to drought than the angiosperm species, suggesting that non-sensitivity to C(a) in these conifers was due to an absent or inactive response/signalling pathway rather than insufficient ABA(f).
authors.affiliation: School of Plant Science, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia.
authors.forename: Scott A M
authors.initials: SA
authors.lastname: McAdam
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Brodribb
authors.forename: John J
authors.initials: JJ
authors.lastname: Ross
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Jordan
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D055864:Droughts; D054046:Plant Stomata / Q000235:genetics / Q000378:metabolism*; D064028:Tracheophyta / Q000235:genetics / Q000378:metabolism*; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D002245:Carbon Dioxide; D000040:Abscisic Acid
references.citation: Plant Cell Environ. 2008 Sep;31(9):1299-306
references.pmid: 18541006
references.citation: Tree Physiol. 2009 Feb;29(2):183-90
references.pmid: 19203943
references.citation: Physiol Plant. 2008 Jun;133(2):417-25
references.pmid: 18282191
references.citation: Funct Plant Biol. 2004 Jul;31(6):659-669
references.pmid: 32688937
references.citation: New Phytol. 2004 Jun;162(3):663-670
references.pmid: 33873766
references.citation: Trends Plant Sci. 2002 Jan;7(1):41-8
references.pmid: 11804826
references.citation: Plant Physiol. 1978 Oct;62(4):670-4
references.pmid: 16660580
references.citation: Nature. 2007 Aug 30;448(7157):1037-41
references.pmid: 17728755
references.citation: Annu Rev Plant Physiol Plant Mol Biol. 2001 Jun;52:627-658
references.pmid: 11337411
references.citation: Plant Physiol. 1978 Sep;62(3):413-7
references.pmid: 16660528
references.citation: Plant Physiol. 2010 Jul;153(3):1435-42
references.pmid: 20472750
references.citation: Planta. 1975 Jan;125(3):243-59
references.pmid: 24435438
references.citation: Plant J. 2009 Jul;59(2):207-20
references.pmid: 19302418
references.citation: New Phytol. 2008;180(3):642-651
references.pmid: 18700860
references.citation: Planta. 1985 Jan;163(1):105-18
references.pmid: 24249275
references.citation: Proc Natl Acad Sci U S A. 2006 May 9;103(19):7506-11
references.pmid: 16651523
references.citation: Plant Cell Environ. 1996 Oct;19(10):1188-94
references.pmid: 11539326
references.citation: Tree Physiol. 2001 Jul;21(11):765-70
references.pmid: 11470663
references.citation: J Exp Bot. 2003 Sep;54(390):2141-7
references.pmid: 12867546
references.citation: Plant Physiol. 2009 Dec;151(4):2018-27
references.pmid: 19864375
references.citation: New Phytol. 2009 Aug;183(3):839-847
references.pmid: 19402882
references.citation: Plant Physiol. 2009 Jan;149(1):575-84
references.pmid: 19011001
references.citation: Plant Physiol. 2006 Feb;140(2):771-8
references.pmid: 16407445
references.citation: Am J Bot. 2009 Oct;96(10):1779-86
references.pmid: 21622298
references.citation: New Phytol. 2001 Feb;149(2):247-264
references.pmid: 33874628
references.citation: New Phytol. 2002 Dec;156(3):351-361
references.pmid: 33873577