Stability of Plant Defensive Traits Among Populations in Two Eucalyptus Species Under Elevated Carbon Dioxide

Abstract

Plant secondary metabolites (PSMs) mediate a wide range of ecological interactions. Investigating the effect of environment on PSM production is important for our understanding of how plants will adapt to large scale environmental change, and the extended effects on communities and ecosystems. We explored the production of PSMs under elevated atmospheric carbon dioxide ([CO(2)]) in the species rich, ecologically and commercially important genus Eucalyptus. Seedlings from multiple Eucalyptus globulus and E. pauciflora populations were grown in common glasshouse gardens under elevated or ambient [CO(2)]. Variation in primary and secondary chemistry was determined as a function of genotype and treatment. There were clear population differences in PSM expression in each species. Elevated [CO(2)] did not affect concentrations of individual PSMs, total phenolics, condensed tannins or the total oil yield, and there was no population by [CO(2)] treatment interaction for any traits. Multivariate analysis revealed similar results with significant variation in concentrations of E. pauciflora oil components between populations. A [CO(2)] treatment effect was detected within populations but no interactions were found between elevated [CO(2)] and population. These eucalypt seedlings appear to be largely unresponsive to elevated [CO(2)], indicating stronger genetic than environmental (elevated [CO(2)]) control of expression of PSMs.

Responses of leaf beetle larvae to elevated [CO2] and temperature depend on Eucalyptus species

“…Eucalyptus species are rich in carbon-based secondary defence compounds, such as phenolics (Moore et al 2004), that are expected to increase at C E (Coley et al 2002), including in fully expanded E. tereticornis leaves (Lawler et al 1997). Contrary to this expectation, however, TP in flush leaves either decreased (E. tereticornis) or showed no response to C E (E. robusta); the absence of a C E effect on TP seen in E. robusta was also in accordance with another study on fully expanded leaves of Eucalyptus globulus (McKiernan et al 2012). In a recent review on the effects of plant secondary compounds at C E , it was observed that there was an increase in phenolic compounds in approximately 50 % of studies, while 7 % of studies showed a decrease and the remaining showed no effect (Ryan et al 2010).…”

“…The secondary chemistry of Eucalyptus is considerably complex and differs between species (Moore et al 2004;McKiernan et al 2012), and this may impact insect survival. Damage to the midgut of P. atomaria feeding on resistant Eucalyptus grandis clones, ultimately resulting in larval death, has previously been observed and may be a result of secondary metabolites acting synergistically or being converted within the insect to a toxic byproduct (Henery et al 2008).…”

Plant growth and leaf-spot severity on eucalypt at different CO2concentrations in the air

“…For the root dry matter weight, only the treatment with 1,147±216 µmol mol -1 CO 2 had significantly higher values than the other treatments. Otherwise, Novriyanti et al (2012) observed no positive effects of elevated CO 2 concentrations on growth of eucalypts, despite increases on net photosynthetic rate. The increase in plant height and shoot dry weight, as observed in the present study, was also observed by Santos et al (2013) and Ghini et al (2014), in clonal eucalypt plantlets grown under high air-CO 2 concentrations for approximately 60 days.…”

“…Braga et al (2006) reported a significant increase in phytoalexin production in two soybean cultivars at 720 μmol mol -1 CO 2 , in comparison to an environment with 360 μmol mol -1 . However, McKiernan et al (2012) verified that elevated CO 2 concentration did not affect contents of secondary metabolites, total phenolics, condensed tannins, or the total oil yield of Eucalyptus globulus and Eucalyptus pauciflora.…”

Effect of NaCl and iron oxide nanoparticles on Mentha piperita essential oil composition

“…In addition, essential oil also plays a prominent role in plant-plant interplays with an evolutionary origin for communication (Langenheim 1994;Batish et al 2008). While essential oil biosynthesis in plants has genetic determination, environmental conditions also affect its production (McKiernan et al 2012;Sadeghi et al 2014).…”