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Significant contribution from foliage-derived ABA in regulating gas exchange in Pinus radiata
Citation
Mitchell, PJ and McAdam, SAM and Pinkard, EA and Brodribb, TJ, Significant contribution from foliage-derived ABA in regulating gas exchange in Pinus radiata, Tree Physiology, 37, (2) pp. 236-245. ISSN 0829-318X (2017) [Refereed Article]
Copyright Statement
Copyright 2016 The authors
DOI: doi:10.1093/treephys/tpw092
Abstract
The complex regulatory system controlling stomata involves physical and chemical signals that affect guard cell turgor to bring about changes in stomatal conductance (gs). Abscisic acid (ABA) closes stomata, yet the mechanisms controlling foliar ABA status in tree species remain unclear. The importance of foliage-derived ABA in regulating gas exchange was evaluated under treatments that affected phloem export through girdling and reduced water availability in the tree species, Pinus radiata (D. Don). Branch- and whole-plant girdling increased foliar ABA levels leading to declines in gs, despite no change in plant water status. Changes in gs were largely independent of the more transient increases in foliar non-structural carbohydrates (NSC), suggesting that gradual accumulation of foliar ABA was the primary mechanism for reductions in gs and assimilation. Whole-plant girdling eventually reduced root NSC, hindering root water uptake and decreasing foliar water potential, causing a dramatic increase in ABA level in leaves and concentrations in the xylem sap of shoots (4032 ng ml-1), while root xylem sap concentrations remained low (43 ng ml-1). Contrastingly, the drought treatment caused similar increases in xylem sap ABA in both roots and shoots, suggesting that declines in water potential result in relatively consistent changes in ABA along the hydraulic pathway. ABA levels in plant canopies can be regulated independently of changes in root water status triggered by changes by both phloem export and foliar water status.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | ABA, drought, girdling, non-structural carbohydrates, phloem transport, stomatal conductance |
| Research Division: | Biological Sciences |
| Research Group: | Plant biology |
| Research Field: | Plant physiology |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding knowledge |
| Objective Field: | Expanding knowledge in the environmental sciences |
| UTAS Author: | McAdam, SAM (Dr Scott McAdam) |
| UTAS Author: | Brodribb, TJ (Professor Tim Brodribb) |
| ID Code: | 112466 |
| Year Published: | 2017 (online first 2016) |
| Funding Support: | Australian Research Council (DP140100666) |
| Web of Science® Times Cited: | 18 |
| Deposited By: | Plant Science |
| Deposited On: | 2016-11-11 |
| Last Modified: | 2017-11-03 |
| Downloads: | 0 |
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