The variability of population and individual traits of medicinal plant Valeriana officinalis L. var. officinalis Mikan under different site conditions

Purpose:The purpose of investigations was to evaluate the effect of site conditions on the variability of traits of Valeriana officinalis L. var. officinalis. Materials and methods:The studies were carried out in the years 2014-2016 in two study areas consisting of patches of Filipendulion ulmariae with a substantial share of low- and medium-growing perennials (Patch I), tall-growing perennials (Patch II), as well as tall-growing perennials and shrubs (Patch III).  Results:Similar tendencies were observed in both study areas. The plant and cryptogam cover showed neither spatial nor temporal variability, while the height of neighbouring plants, as well as the pH and moisture of soil, augmented in subsequent patches. The lowest abundance of subpopulation Valeriana officinalis was noted in Patch III. During the study period seedlings and juveniles were not found in any of the patches, whilst the share of vegetative genets diminished gradually at the cost of generative individuals and ramet clusters. The majority of individual traits (e.g. number of ramets, radical leaves and flowers, number and height of flowering stems) augmented in successive patches, while the number of radical leaves in generative individuals and ramet clusters, as well as the height of flowering stems and number of flowers, additionally augmented in consecutive years. Conclusions: The considerable share of vegetative individuals in sites dominated by low-statured plants  contributes to rejuvenation of subpopulations. The clonal growth might protect all subpopulations from regression. The substantial production and dimensions of flowering stems in vicinity of  tall-growing perennials enlarges the chances for successful pollination and seed dispersal.