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Lavatera arborea

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Common name: Tree Mallow

Symptoms induced in controlled conditions (fumigation with ozone)

Fumigation of Lavatera arborea with enhanced ozone levels in Open Top Chambers (OTCs) produced an interveinal yellowing restricted to older leaves. This response is similar to that found for the related species Malva sylvestris and may represent an accelerated senescence, which is difficult to distinguish under natural conditions from natural senescence or senescence induced by other stresses. For this reason, caution has to be taken before assigning this type of effect to ozone in the field. A complementary microscopy analysis may help in making a correct diagnosis.

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