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Augmentation of abscisic acid (ABA) levels by drought does not induce short-term stomatal sensitivity to CO2 in two divergent conifer species

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McAdam, SAM and Brodribb, TJ and Ross, JJ and Jordan, GJ (2011) Augmentation of abscisic acid (ABA) levels by drought does not induce short-term stomatal sensitivity to CO2 in two divergent conifer species. Journal of Experimental Botany, 62 (1). pp. 195-203. ISSN 0022-0957

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Abstract

The stomata of conifers display very little short-term response to changes in atmospheric CO2 concentration (Ca), whereas the stomatal responses of angiosperms to Ca increase in response to water stress. This behaviour of angiosperm stomata appears to be dependent on foliar levels of abscisic acid (ABAf). Here two alternative explanations for the stomatal insensitivity of conifers to Ca are tested: that conifers have either low ABAf or a higher or absent threshold for ABA-induced sensitivity. The responsiveness of stomatal conductance (gs) to a sequence of transitions in Ca (386, 100, and 600 mmol mol21) was recorded over a range of ABAf 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 ABAf following drought, conifer stomata remained insensitive to changes in Ca whereas angiosperm stomata showed enhanced sensitivity with increasing ABAf. The conifers, however, had much higher ABAf prior to drought than the angiosperm species, suggesting that nonsensitivity to Ca in these conifers was due to an absent or inactive response/signalling pathway rather than insufficient ABAf.

Item Type: Article
Keywords: Abscisic acid angiosperm carbon dioxide conifer drought stomata stomatal conductance
Journal or Publication Title: Journal of Experimental Botany
Page Range: pp. 195-203
ISSN: 0022-0957
Identification Number - DOI: 10.1093/jxb/erq260
Additional Information: The definitive publisher-authenticated version is available online at: www.oxfordjournals.org
Date Deposited: 19 Jan 2011 06:11
Last Modified: 18 Nov 2014 04:15
URI: http://eprints.utas.edu.au/id/eprint/10595
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