Carins Murphy, MR and Jordan, GJ and Brodribb, TJ, Cell expansion not cell differentiation predominantly co-ordinates veins and stomata within and among herbs and woody angiosperms grown under sun and shade, Annals of Botany, 118, (6) pp. 1127-1138. ISSN 0305-7364 (2016) [Refereed Article]
Copyright 2016 The Author
Background and aims: It has been proposed that modification of leaf size, driven by epidermal cell size, balances leaf water supply (determined by veins) with transpirational demand (generated by stomata) during acclimation to local irradiance. We aimed to determine whether this is a general pattern among plant species with contrasting growth habits.
Methods: We compared observed relationships between leaf minor vein density, stomatal density, epidermal cell size and leaf size in four pairs of herbs and woody species from the same families grown under sun and shade conditions with modelled relationships assuming vein and stomatal densities respond passively to epidermal cell expansion. Leaf lignin content was also quantified to assess whether construction costs of herbaceous leaf veins differ from those of woody plants and the leaf mass fraction invested in veins.
Key Results: Modelled relationships accurately described observed relationships, indicating that in all species, co-ordinated changes to the density of minor veins and stomata were mediated by a common relationship between epidermal cell size, vein density and stomatal density, with little or no impact from stomatal index. This co-ordination was independent of changes in leaf size and is likely to be an adaptive process driven by the significant proportion of biomass invested in veins (13·1 % of sun leaf dry weight and 21·7 % of shade leaf dry weight). Relative costs of venation increased in the shade, intensifying selective pressure towards economizing investment in vein density.
Conclusions: Modulation of epidermal cell size appears to be a general mechanism among our experimental species to maintain a constant ratio between leaf anatomical traits that control leaf water fluxes independently of habit. We propose that this process may co-ordinate plasticity in hydraulic supply and demand in the majority of eudicot angiosperms.
|Item Type:||Refereed Article|
|Keywords:||epidermal cell size, herbs, hydraulics, leaf size, leaf economics, stomatal density, vein density, woody plants|
|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:||Carins Murphy, MR (Miss Madeline Carins-Murphy)|
|UTAS Author:||Jordan, GJ (Professor Greg Jordan)|
|UTAS Author:||Brodribb, TJ (Professor Tim Brodribb)|
|Funding Support:||Australian Research Council (DP140100666)|
|Web of Science® Times Cited:||48|
|Deposited By:||Plant Science|
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