CNR ExploRA

Articolo in rivista, 2019, ENG, 10.1016/j.scitotenv.2019.07.288

Ozone-induced impairment of night-time stomatal closure in O3-sensitive poplar clone is affected by nitrogen but not by phosphorus enrichment

Hoshika Y., De Carlo A., Baraldi R., Neri L., Carrari E., Agathokleous E., Zhang L., Fares S., Paoletti E.

Istituto di Ricerca sugli Ecosistemi Terrestri (IRET), National Research Council (CNR), Via Madonna del Piano, I-50019 Sesto Fiorentino, Italy Istituto di Bioeconomia (IBE), National Research Council (CNR), via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence, Italy Istituto di Bioeconomia (IBE), National Research Council (CNR), Via P. Gobetti, 101, 40129 Bologna, Italy Institute of Ecology, Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science and Technology (NUIST), Nanjing, Jiangsu 210044, China College of Horticulture and Landscape Architecture, Northeast Agricultural University, Changjiang Road 600, 150030 Harbin, China Research Centre for Forestry and Wood, Council for Agricultural Research and Economics, Roma, Italy

Nocturnal transpiration may be a key factor influencing water use in plants. Tropospheric ozone (O3) and availability of nutrients such as nitrogen (N) and phosphorus (P) in the soil can affect daytimewater use through stomata, but the combined effects of O3, N and P on night-time stomatal conductance (gs) are not known. We investigated the effects of O3 and soil availability of N and P on nocturnal gs and the dynamics of stomatal response after leaf severing in an O3-sensitive poplar clone (Oxford) subjected to combined treatments over a growing season in an O3 free air controlled exposure (FACE) facility. The treatments were two soil N levels (0 and 80 kg N ha-1; N0 and N80), three soil P levels (0, 40 and 80 kg P ha-1; P0, P40 and P80) and three O3 levels(ambient concentration, AA [35.0 ppb as hourly mean]; 1.5 × AA; 2.0 × AA). The analysis of stomatal dynamics after leaf severing suggested that O3 impaired stomatal closure execution. As a result, nocturnal gs was increased by 2.0 × AA O3 in August (+39%) and September (+108%). Night-time gswas correlatedwith POD0 (phytotoxic O3 dose) and increased exponentially after 40 mmol m-2 POD0. Such increase of nocturnal gswas attributed to the emission of ethylene due to 2.0 × AA O3 exposure, while foliar abscisic acid (ABA) or indole-3-acetic acid (IAA) did not affect gs at night. Interestingly, the O3-induced stomatal opening at night was limited by N treatments in August, but not limited in September. Phosphorus decreased nocturnal gs, although P did not modify the O3-induced stomatal dysfunction. The results suggest that the increased nocturnal gs may be associated with a need to improve N acquisition to cope with O3 stress.

Science of the total environment 692 , pp. 713–722