Ozone effects on three Sambucus species.

The onset and development of symptoms of three Sambucus species, S. ebulus, S. nigra and S. racemosa were studied in 2002 under three different experimental conditions, in charcoal filtered air (CF), and in two ozone enriched treatment: non filtered air plus 40 ppb ozone (NF+), and non filtered air plus 70 ppb ozone (NF++). The herb S. ebulus was more sensitive than the shrubs S. racemosa and S. nigra. Some plants of the three species showed visible injury below the AOT40 threshold of 10,000 ppb.h, established for protection of vegetation. Ozone produced a decrease in chlorophyll content in S. ebulus, and impaired both stomatal conductance and net photosynthesis in S. ebulus and S. nigra. A complementary study in 2004 with S. ebulus, confirmed a decrease in chlorophyll content after fumigation, associated to a decrease in N content of the leaves. Since S. ebulus is a widespread species in Europe and it is very sensitive to ozone, it could be a very appropriate plant for the biomonitoring studies across large areas in this continent.