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Effect of ozone and sulphur dioxide on mycorrhizae of Pinus halepensis Miller

Abstract:

Little information exists on the effect of ozone (O3) and sulphur dioxide (SO2) on Pinus halepensis Miller. The objective of this work was to determine the effect of these gaseous pollutants alone or in combination on biomass and mycorrhizae of P halepensis. Seedlings were treated for 1 year with filtered air (control), 50 ppb O3, 40 ppb SO2 or a mixture of 59 ppb O3 + 40 ppb SO2, O3 and SO2 treatments had no significant effect on shoot and root biomass and a slight reduction on percentage of mycorrhizal colonization was noted with SO2. However, these parameters were significantly reduced when the pollutants acted in combination. Morphological alterations of mycorrhizae were also noted, with a reduction in the coralloid structures in favour of simple ones. Moreover, a change in species composition was observed: the ectomycorrhizae probably formed by Suillus species being replaced by ectendomycorrhizae in the O3 + SO2 treatment.