McKiernan, AB and Potts, BM and Hovenden, MJ and Brodribb, TJ and Davies, NW and Rodemann, T and McAdam, SAM and O'Reilly-Wapstra, JM, A water availability gradient reveals the deficit level required to affect traits in potted juvenile Eucalyptus globulus, Annals of Botany, 119, (6) pp. 1043-1052. ISSN 0305-7364 (2017) [Refereed Article]
Copyright 2017 The Author
Background and aims: Drought leading to soil water deficit can have severe impacts on plants. Water deficit may lead to plant water stress and affect growth and chemical traits. Plant secondary metabolite (PSM) responses to water deficit vary between compounds and studies, with inconsistent reports of changes to PSM concentrations even within a single species. This disparity may result from experimental water deficit variation among studies, and so multiple water deficit treatments are used to fully assess PSM responses in a single species.
Methods: Juvenile Eucalyptus globulus were grown for 8 weeks at one of ten water deficit levels based on evapotranspiration from control plants (100 %). Treatments ranged from 90 % of control evapotranspiration (mild water deficit) to 0 % of control evapotranspiration (severe water deficit) in 10 % steps. Plant biomass, foliar abscisic acid (ABA) levels, Ψleaf, leaf C/N, selected terpenes and phenolics were quantified to assess responses to each level of water deficit relative to a control.
Key Results: Withholding ≥30 % water resulted in higher foliar ABA levels and withholding ≥40 % water reduced leaf water content. Ψleaf became more negative when ≥60 % water was withheld. Plant biomass was lower when ≥80 % water was withheld, and no water for 8 weeks (0 % water) resulted in plant death. The total oil concentration was lower and C/N was higher in dead and desiccated juvenile E. globulus leaves (0 % water). Concentrations of individual phenolic and terpene compounds, along with condensed tannin and total phenolic concentrations, remained stable regardless of water deficit or plant stress level.
Conclusions: These juvenile E. globulus became stressed with a moderate reduction in available water, and yet the persistent concentrations of most PSMs in highly stressed or dead plants suggests no PSM re-metabolization and continued ecological roles of foliar PSMs during drought.
|Item Type:||Refereed Article|
|Keywords:||Eucalyptus globulus, drought, water stress, secondary metabolite, PSM, terpene, phenolic, macrocarpal, abscisic acid, tannin, water potential|
|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:||McKiernan, AB (Mr Adam McKiernan)|
|UTAS Author:||Potts, BM (Professor Brad Potts)|
|UTAS Author:||Hovenden, MJ (Associate Professor Mark Hovenden)|
|UTAS Author:||Brodribb, TJ (Professor Tim Brodribb)|
|UTAS Author:||Davies, NW (Associate Professor Noel Davies)|
|UTAS Author:||Rodemann, T (Dr Thomas Rodemann)|
|UTAS Author:||McAdam, SAM (Dr Scott McAdam)|
|UTAS Author:||O'Reilly-Wapstra, JM (Dr Julianne O'Reilly-Wapstra)|
|Funding Support:||Australian Research Council (DP140100666)|
|Web of Science® Times Cited:||2|
|Deposited By:||Plant Science|
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