Exogenous Isoprene Confers Physiological Benefits in a Negligible Isoprene Emitter (Acer monspessulanum L.) Under Water Deficit

Elena Ormeño (1) , Justine Viros (1) , Jean-Philippe Mevy (1) , Alain Tonetto (2) , Amélie Saunier (1, 3) , Anne Bousquet-Mélou (1) , Catherine Fernandez (1)

1 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
2 FRSCM - Fédération des Sciences Chimiques de Marseille
3 University of Eastern Finland

Isoprene, the main volatile released by plants, is known to protect the photosynthetic apparatus in isoprene emitters submitted to oxidative pressures caused by environmental constraints. Whether ambient isoprene contributes to protect negligible plant emitters under abiotic stress conditions is less clear, and no study has tested if ambient isoprene is beneficial during drought periods in plant species that naturally release negligible isoprene emissions. This study examines the effect of exogenous isoprene (20 ppbv) on net photosynthesis, stomatal conductance and production of H2O2 (a reactive oxygen species: ROS) in leaves of Acer monspessulanum (a negligible isoprene emitter) submitted to three watering treatments (optimal, moderate water stress and severe water stress). Results showed that A. monspessulanum exhibited a net photosynthesis increase (+30%) and a relative leaf H2O2 decrease when saplings were exposed to an enriched isoprene atmosphere compared to isoprene-free conditions under moderate water deficit. Such physiological improvement under isoprene exposure was not observed under optimal watering or severe water stress. These findings suggest that when negligible isoprene emitters are surrounded by a very high concentration of isoprene in the ambient air, some plant protection mechanism occurs under moderate water deficit probably related to protection against ROS damage eventually impeding photosynthesis drop.

Keywords: oxidative pressure; isoprene protection; water deficit; negligible terpene emitters; reactive oxygen species; abiotic stress; allelochemicals

Domains: Environmental Sciences; Global Changes; Environmental Sciences; Biodiversity and Ecology

Elena Ormeño, Justine Viros, Jean-Philippe Mevy, Alain Tonetto, Amélie Saunier, et al.. Exogenous Isoprene Confers Physiological Benefits in a Negligible Isoprene Emitter (Acer monspessulanum L.) Under Water Deficit. Plants, 2020, 9 (2), pp.1-14/159. ⟨10.3390/plants9020159⟩. ⟨hal-02462035⟩