Monoterpene and sesquiterpene emissions of three Mediterranean species through calcareous and siliceous soils in natural conditions

Little is known about terpene emissions released by plants in response to abiotic factors, except for climate-related factors. Standard emissions (E_S) of monoterpenes (E_SM) and sesquiterpenes (E_SS) of Rosmarinus officinalis, Pinus halepensis and Cistus albidus in siliceous and calcareous sites were examined. Their dependency on some nutrients in these soils was also analyzed. The study was carried out in the south of France at the end of March, when C. albidus exhibited a leaf growth state, while the other two species exhibited a pre-budbreak state. The results revealed that E_S of all major monoterpenes released by R. officinalis and E_S of α-pinene and α-humulene of P. halepensis were higher in plants growing in calcareous soils. In contrast, for C. albidus, E_SM and E_S of β-bourbonene and α-humulene were higher in siliceous soils. E_SM of all species was mainly correlated with nitrogen (N) and available phosphorous (P_A), while dependency on Ca²⁺ or K⁺ was variable. None of these nutrients was significantly correlated with E_SS, suggesting that sesquiterpene synthesis pathway requires different nutrient supplies. While higher soil nutrient content stimulated E_SM of R. officinalis and P. halepensis, it had a negative effect on E_SM of C. albidus, probably because C. albidus exhibited a different phenological state. Considering the soil nature, and particularly N and P_A as inputs in plant terpene inventories could hence contribute to obtain more accurate terpene estimates.