Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants  . Issue 3 (11th May 2016)

• Record Type: Journal Article
• Authors: McAdam, Scott A.M.; Brodribb, Timothy J.
• Is Part Of: Plant physiology. Volume 171:Issue 3(2016)
• Page Start: 2008
• Page End: 2016
• Publication Date: 2016-05-11
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.16.00380
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : Small reductions in leaf turgor can trigger foliar ABA biosynthesis in angiosperms, influencing stomatal responses to vapor pressure deficit. Abstract: Stomatal responses to changes in vapor pressure deficit (VPD ) constitute the predominant form of daytime gas-exchange regulation in plants. Stomatal closure in response to increased VPD is driven by the rapid up-regulation of foliar abscisic acid (ABA) biosynthesis and ABA levels in angiosperms; however, very little is known about the physiological trigger for this increase in ABA biosynthesis at increased VPD . Using a novel method of modifying leaf cell turgor by the application of external pressures, we test whether changes in turgor pressure can trigger increases in foliar ABA levels over 20 min, a period of time most relevant to the stomatal response to VPD . We found in angiosperm species that the biosynthesis of ABA was triggered by reductions in leaf turgor, and in two species tested, that a higher sensitivity of ABA synthesis to leaf turgor corresponded with a higher stomatal sensitivity to VPD . In contrast, representative species from nonflowering plant lineages did not show a rapid turgor-triggered increase in foliar ABA levels, which is consistent with previous studies demonstrating passive stomatal responses to changes in VPD in these lineages. Our method provides a new tool for characterizing the response of stomata to water availability.