Intraspecific Variation in Drought Response of Three Populations of Cryptocarya alba and Persea lingue, Two Native Species From Mediterranean Central Chile.

Carolina Alvarez-Maldini,Marta González,Eduardo Cartes,Manuel Acevedo,R Kasten Dumroese

doi:10.3389/fpls.2020.01042

Abstract

An increase in the severity of drought events on Mediterranean climates highlights the need of using plant material adapted to drought during restoration efforts. Thus, we investigated between-population morpho-physiological differences in Cryptocarya alba and Persea lingue, two native species from Mediterranean central Chile, for traits that could effectively discriminate population performance in response to water restriction (WR) testing. Three populations from each species were subjected to WR treatment and physiological, morphological, and growth parameters were assessed at the beginning and at the end of the experiment. In C. alba, the most xeric population displayed smaller plants with mesophyllous leaves and lower photosynthetic rates indicating a resource saving strategy. Moreover, the xeric population performed better during WR than the most mesic populations, exhibiting higher water use efficiency (iWUE) and maintenance of growth rates. All C. alba populations responded equally to WR in terms of morphology and biomass partitioning. In contrast, differences among P. lingue populations were subtle at the morpho-physiological level with no apparent relation to provenance environmental conditions, and no morphological traits were affected by WR. However, in response to WR application, the most mesic population was, as observed through reduction in relative growth rates, more affected than xeric populations. We attribute such discrete differences between P. lingue provenances to the lower distributional range of selected populations. Our results show that relative growth rates in both species, and iWUE only in C. alba, exhibited population specific responses upon WR imposition; these results correspond with the environmental conditions found at the origin of each populations. Both traits could further assist in the selection of populations for restoration according to their response to water stress.

Highlights

The worlds forests will need to cope and adapt to changes that are threatening their natural habitats (Allen et al, 2010; Gilliam, 2016)
At the conclusion of the water restriction (WR) treatment, we noted this relationship changed due to a significant interaction between population x measurement time; Santiago increased AN and no significant differences were observed with Cayumanque or Nacimiento (6.42 ± 0.78 vs. 6.16 ± 0.9 vs. 4.23 ± 0.8 μmol CO2 m-2s-1, respectively); gs and E followed the same pattern as AN
No differences were observed between CC plants from both measurement times and populations, but the WR treatment increased Intrinsic water use efficiency (iWUE) on plants from Nacimiento and Santiago whereas no change was observed for Cayumanque (Figure 2)

Summary

Introduction

The worlds forests will need to cope and adapt to changes that are threatening their natural habitats (Allen et al, 2010; Gilliam, 2016). Habitat heterogeneity across species distribution can lead to variability in plant functional traits in response to environmental factors (Linhart and Grant, 1996; Hufford and Mazer, 2003), indicating that populations within a species experiencing different environmental conditions can differ in phenotypic characteristics and genetic structure (Linhart and Grant, 1996) This intraspecific variation in morpho-physiological traits in response to drought has been reported in a large number of tree species from Mediterranean climates (Gratani et al, 2003; Ramıŕ ez-Valiente et al, 2010; Kaluthota et al, 2015; Kerr et al, 2015; Ramıŕ ez-Valiente and Cavender-Bares, 2017)

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