Nutrient‐rich plants emit a less intense blend of volatile isoprenoids

Abstract

The emission of isoprenoids (e.g. isoprene and monoterpenes) by plants plays an important defensive role against biotic and abiotic stresses. Little is known, however, about the functional traits linked to species-specific variability in the types and rates of isoprenoids emitted and about possible co-evolution of functional traits with isoprenoid emission type (isoprene emitter, monoterpene emitter or both). We combined data for isoprene and monoterpene emission rates per unit dry mass with key functional traits (foliar nitrogen (N) and phosphorus (P) concentrations, and leaf mass per area) and climate for 113 plant species, covering the boreal, wet temperate, Mediterranean and tropical biomes. Foliar N was positively correlated with isoprene emission, and foliar P was negatively correlated with both isoprene and monoterpene emission rate. Nonemitting plants generally had the highest nutrient concentrations, and those storing monoterpenes had the lowest concentrations. Our phylogenetic analyses found that the type of isoprenoid emission followed an adaptive, rather than a random model of evolution. Evolution of isoprenoids may be linked to nutrient availability. Foliar N and P are good predictors of the type of isoprenoid emission and the rate at which monoterpenes, and to a lesser extent isoprene, are emitted.

Isoprene and monoterpene emissions in south-east Australia: comparison of a multi-layer canopy model with MEGAN and with atmospheric observations

“…Emmerson et al (2016) postulated that the discrepancies were due to unrepresentative emission factors, the majority coming from studies both in Australia and overseas on eucalypt saplings under laboratory conditions. The VOC emissions from Australian vegetation may be different in magnitude and behaviour from those studied in the northern temperate regions and in the tropics because Australian vegetation was isolated from other regions for many tens of millions of years and, in general, adapted to infertile deeply weathered ancient soils and a regime of intense fires (Orians and Milewski, 2007), factors that could affect the evolutionary biology of plant VOC emissions (Fernández-Martínez et al, 2017). These questions on VOC synthesis are beyond the scope of this paper.…”

“…Two thirds of the 80 cases have ratios greater than 1. Monoterpene emissions are favoured in nitrogen poor conditions (Fernández-Martínez et al, 2017) in species with a long leaf lifespan (Harrison et al 2013), conditions matching Australia.…”

“…CB05 combines individual monoterpenes into one lumped monoterpene species. Particulate species are processed in a two-bin sectional scheme with inorganic processing via ISORROPIA_II (Fountoukis and Nenes, 2007), and organic processing via the volatility basis set (Shrivastava et al, 2008). A 5 min chemical time step is used and all species are output on an hourly averaged basis.…”

Linking soil's volatilome to microbes and plant roots highlights the importance of microbes as emitters of belowground volatile signals

“…This is further supported by the fact that fertilization treatments of soil have been documented to affect mono‐ and sesquiterpenes emission in plants (Ormeño and Fernandez, ). Similarly, the uptake of soil's nutrients by plants was shown to influence the production of volatiles, as illustrated by the finding that phosphorus foliar concentrations negatively correlated to isoprene and monoterpenes emissions (Fernández‐Martínez et al ., ). Additionally, nutrients might similarly affect volatiles synthetized by bacteria (Garbeva et al ., ).…”

Introduction to a special feature issue – New insights into plant volatiles

“…For example, nutrient availability, which may be strongly affected by the microbial community associated with the plant, can affect volatile emission dramatically. Fernández‐Martínez et al . (in this issue, pp. 773–784) found that foliar nitrogen (N) was positively correlated with isoprene emissions while foliar phosphorus (P) was negatively correlated with isoprene and monoterpene emissions, which can have significant effects on the atmospheric chemistry.…”