Early physiological responses of Pinus pinea L. seedlings infected by Heterobasidion sp.pl. in an ozone-enriched atmospheric environment.
The presence of the American root-rot disease fungus Heterobasidion irregulare Garbel. & Otrosina was detected in Italian coastal pine forests (Pinus pinea L.) in addition to the common native species Heterobasidion annosum (Fries) Brefeld. High levels of tropospheric ozone (O3) as an atmospheric pollutant are usually experienced in Mediterranean pine forests. To explore the effect of interaction between the two Heterobasidion species and ozone pollution on P. pinea, an open-top chamber (OTC) experiment was carried out. Five-year-old P. pinea seedlings were inoculated with the fungal species considered (H. irregulare, H. annosum and mock-inoculation as control), and then exposed in charcoal-filtered open-top chambers (CF-OTC) and non-filtered ozone-enriched chambers (NF+) from July to the first week of August 2010 at the experimental facilities of Curno (North Italy). Fungal inoculation effects in an ozone-enriched environment were assessed as: (i) the length of the inoculation lesion; (ii) chlorophyll a fluorescence (ChlF) responses; and (iii) analysis of resin terpenes. Results showed no differences on lesion length between fungal and ozone treatments, whereas the short-term effects of the two stress factors on ChlF indicate an increased photosynthetic efficiency, thus suggesting the triggering of compensation/repair processes. The total amount of resin terpenes is enhanced by fungal infection of both species, but depressed by ozone to the levels observed in mock-inoculated plants. Variations in terpene profiles were also induced by stem base inoculations and ozone treatment. Ozone might negatively affect terpene defences making plants more susceptible to pathogens and insects.
Department of Agri-Food Productions and Environmental Sciences (DiSPAA), Università degli Studi di Firenze, Piazzale delle Cascine 28, I-50144 Florence, Italy martina.pollastrini@unifi.it.
Martina
M
Pollastrini
Institute for Sustainable Plant Protection (IPSP) - Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence, Italy.
Nicola
N
Luchi
Institute of Biosciences and Bioresources (IBBR) - Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence, Italy.
Marco
M
Michelozzi
Department of Mathematics and Physics, Università Cattolica del Sacro Cuore di Brescia, Via dei Musei 41, 25121 Brescia, Italy.
Giacomo
G
Gerosa
Department of Mathematics and Physics, Università Cattolica del Sacro Cuore di Brescia, Via dei Musei 41, 25121 Brescia, Italy.
Riccardo
R
Marzuoli
Department of Agri-Food Productions and Environmental Sciences (DiSPAA), Università degli Studi di Firenze, Piazzale delle Cascine 28, I-50144 Florence, Italy.
Filippo
F
Bussotti
Department of Agri-Food Productions and Environmental Sciences (DiSPAA), Università degli Studi di Firenze, Piazzale delle Cascine 28, I-50144 Florence, Italy.
Paolo
P
Capretti
D001487:Basidiomycota; D002734:Chlorophyll / Q000737:chemistry; D000077194:Chlorophyll A; D010126:Ozone / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects / Q000502:physiology; D028223:Pinus / Q000187:drug effects / Q000382:microbiology* / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D012116:Resins, Plant / Q000032:analysis; D036226:Seedlings / Q000187:drug effects / Q000382:microbiology / Q000502:physiology; D013729:Terpenes / Q000032:analysis
D012116:Resins, Plant; D013729:Terpenes; D002734:Chlorophyll; D010126:Ozone; D000077194:Chlorophyll A
Mediterranean; fungal inoculation; pine; root-rot pathogens; terpene; tropospheric ozone