Seasonal dynamics of element accumulation in highland rush (Juncus trifidus, L.)

Abstract

Seasonal variation influences the elemental composition of alpine plants yet remains understudied due to sampling challenges. This study investigates monthly changes in macro- and micronutrient concentrations in Juncus trifidus L., a stress-tolerant alpine species, across leaf blades and basal sheaths over one year in the Low Tatras (Slovakia). Using energy-dispersive X-ray fluorescence spectrometry, 14 elements were consistently detected and analysed. Results revealed clear seasonal and organ-specific differences. Leaf tissues showed higher concentrations of S, Ca, Mn, and Zn, reflecting their role in active metabolism. In contrast, sheaths accumulated more Fe, Pb, and Cl during specific seasons, suggesting storage or detoxification functions. Principal component analysis identified distinct multivariate patterns, with some factors showing inverse relationships between essential and potentially toxic elements, indicating physiological trade-offs and stress responses. Seasonal peaks in elements such as K and Rb in summer, and S and Ca in spring, corresponded with growth phases and environmental conditions. These findings underscore the importance of temporal dynamics in nutrient uptake and allocation, offering insights into alpine plant adaptation and supporting the use of J. trifidus as a bioindicator in ecological monitoring.