Geographic variation and plasticity to water and nutrients in Pelargonium australe

Abstract

Summary• Here, patterns of phenotypic plasticity and trait integration of leaf characteristics in six geographically discrete populations of the perennial herb Pelargonium australe were compared. It was hypothesized that populations would show local adaptation in trait means, but similar patterns of plasticity and trait integration. Further, it was questioned whether phenotypic plasticity was positively correlated with environmental heterogeneity and whether plasticity for water-use traits in particular was adaptive.• Seedlings were grown in a glasshouse at six combinations of water and nutrient availability. Leaf anatomical, morphological and gas exchange traits were measured.• High amounts of plasticity in leaf traits were found in response to changes in growth conditions and there was evidence of local adaptation among the populations. While there were significant correlations between plasticity and environmental heterogeneity, not all were positive. Notably, patterns of plasticity and trait integration varied significantly among populations. Despite that variation, some of the observed plasticity was adaptive: fitness was correlated with conservative water use when water was limiting.• Pelargonium arrived in Australia ∼ 5 million yr ago. It is concluded here that high amounts of plasticity, in some cases adaptive, and weak integration among traits may be key to the spread and success of this species.

The plasticity of phenotypic integration in response to light and water availability in the pepper grass, Lepidium bonariense

“…The published literature on plants is very much equivocal with regard to how trait means and covariances should respond to different environmental conditions. Some species show a change in mean trait size and covariances across environments (Lechowicz and Blais 1988;Schlichting 1989;Pigliucci et al 1997;Pigliucci and Schlichting 1998;Callahan and Waller 2000;Pigliucci and Hayden 2001;Pigliucci 2002;Tonsor and Scheiner 2007;Nicotra et al 2007;Brock and Weinig 2007), while others only exhibit a change in mean trait size with the covariance structure remaining constant (Waitt and Levin 1993;Herrera et al 2002;Pigliucci and Kolodynska 2002a, b;Kolodynska and Pigliucci 2003;Bidart-Bouzat et al 2004;Bossdorf and Pigliucci 2009). It is likely that the relationship between plasticity and trait integration will be species-specific making generalizations on this relationship difficult, if not impossible.…”

Variation in tolerance to drought among Scandinavian populations of Arabidopsis lyrata

“…In particular, the ability to cope with drought stress has received substantial attention in studies of both natural populations (e.g. Nicotra et al 2007) and crops (Chaves and Oliveira 2004), and is likely to become even more important in the future, as climate change scenarios predict higher temperatures and increased aridity in many parts of the world (Canadell et al 2007;Angilletta 2009). Predicting the evolutionary consequences of changes in the incidence of drought stress requires information about the extent to which drought response traits vary genetically within and among populations.…”

Variation in and adaptive plasticity of flower size and drought-coping traits

“…Plasticity in stomatal density aids in the regulation of water loss (Xu and Zhou 2008;Fraser et al 2009;Maherali et al 2010), while an increase in root number or size facilitates water uptake and/or storage (Sultan and Bazzaz 1993;Heschel et al 2004;Gianoli and Gonzalez-Teuber 2005;Mal and Lovett-Doust 2005). Physiologically, plants may exhibit plasticity in stomatal conductance, whereby they close their stomata to limit water loss under drought, increasing instantaneous water-use efficiency (WUE), which is the ratio of carbon gained via photosynthesis to water lost via transpiration (Heschel et al 2004;Caruso et al 2006;Sherrard and Maherali 2006;Nicotra et al 2007;Maherali et al 2010;Lázaro-Nogal et al 2015). Plasticity in integrative WUE has been observed using stable carbon isotopes (d 13 C; Aspelmeier and Leuschner 2004;Franks 2011;Edwards et al 2012;Kenney et al 2014), which are often more reliable than instantaneous measures, because d 13 C reflects WUE integrated over longer periods of time.…”