Plant biomonitoring: impact of urban environment on seasonal dynamics of storage substances and chlorophylls of Oleander

In the present study seasonal changes of chlorophyll content and storage substances related to the
metabolic response of the widespread, evergreen plant oleander (Nerium oleander) to air pollution
were investigated. Mature leaves of oleander shrubs, grown at five sites of differing levels of air
pollution in the center and the suburbs of the Athens Metropolitan area, were examined during the
course of a year. Soluble sugars, starch and total lipid content of the leaves showed a peak at the
end of the cold season, while a decline was detected during the main growth period. Leaf
chlorophyll content was increased during spring. It seems likely that the level of air pollution in
Athens did not affect the concentration and the seasonal pattern of storage substances at the leaf
level. Elevated chlorophyll content was estimated in the polluted with oxides of nitrogen sites. In
contrast, leaf chlorophyll content declined in sites with ozone pollution.