Taraxacum officinale (Asteraceae) in the urban environment: seasonal fluctuations of plant traits and their relationship with meteorological factors

Plants can be used as effective bioindicators of the quality of the urban habitat. In this study, physiological traits were examined in plants growing outdoors, in the proximity of a road. All material was collected from robust, well-grown plants. All measurements were performed during the generative phase. Here, the evaluations of some gravimetric parameters (fresh weight, turgid weight, dry weight, water content, ash content) and physiological parameters (initial water content, mineral content, organic content, organic content/mineral content ratio, succulence, mineral deposition in tissues, tissues density, leaf relative water content, specific leaf area) were calculated for Taraxacum officinale from urban unmanaged areas, across the different seasons (winter, spring, summer, fall). One-way analysis of variance (ANOVA) was used to compare these traits in leaves, scapes, and roots. Initial water content and relative water content are good indicators of water status in T. officinale. With regard to succulence, its level was generally considerably lower in roots than in aboveground organs. The mineral content differed significantly among plant organs. For all the parameters analyzed, the most considerable seasonal differences were found in leaves. The Spearman correlations were calculated for the relations between plant traits. Mineral deposition in tissues is the most sensitive parameter, regardless of the organ. The data were subjected to Spearman correlation and linear regression analysis for each physiological parameter and some meteorological factors. The strongest association was generally found with the wind. Variations in the investigated parameters in roots and scapes are more associated with meteorological factors. Taraxacum officinale plants are able to tolerate urban conditions in proximity to a road. Plastic responses to environmental cues make the plant useful in biomonitoring the quality of the urban habitat.