Dependence of dandelion (Taraxacum Officinale Wigg.) seed reproduction indices on intensity of motor traffic pollution

Abstract

Dandelion (Taraxacum offcinale Wigg.) seed reproduction indices such as the total number of seeds, the number of normally developed seeds and underdeveloped seeds per anthodium, and seed weight are suggested to assess the level of environmental pollution (bioindication). However, the non-monotonic dose-response dependences (hormesis and paradoxical effects) of these indices are insuffciently explored upon exposure to pollution. We studied the dependence of some T. offcinale seed reproduction indices on intensity of motor traffc pollution in wide range of values over 2 years of observation. In 2010, the increase in traffc intensity induced a monotonic increase in the total seed number and the number of normally developed seeds. Besides, motor traffc pollution decreased the number of undeveloped seeds and seed weight in comparison with the control. In 2011, for all studied T. offcinale indices except seed weight, complicated non-monotonic dependences on traffc intensity were found that could be attributed to paradoxical effects. It is hypothesised that the signifcant differences in the studied dependencies in 2010–2011 were caused by changes in weather conditions because traffc intensity did not differ sig-nifcantly between the two observation years.