Distribution and Resorption Efficiency of Macroelements (N, P, K, Ca, and Mg) in Organs of Rumex alpinusL. in the Alps and the Giant (Krkonoše) Mountains

Rumex alpinus, an alpine nitrophilous species, is a troublesome weed in pastures. Nutrient uptake and distributions in the organs of Rumex alpinusare not well-studied. We aimed to determine the distribution of macroelements in organs of Rumex alpinustogether with the nitrogen-phosphorus potassium ratio (NPK) and the resorption efficiency of N, P, K, calcium (Ca), and magnesium (Mg) in the Alps of Austria, Italy, and the Krkonoše (Giant) Mountains, Czech Republic. The pseudo-total and plant-available N, P, K, Ca, and Mg in soils and organs of Rumex alpinus(emerging, mature, and senescent leaves, petioles, stems, and rhizomes) were extracted with aqua regiaand Mehlich-3 procedures, respectively, followed by inductively coupled plasma-optical emission spectrometry. The contents of total and available macroelements in the soils reflected high variability with localities. There was a significant effect of locality and organs on the element contents, indicating differences in nutrition. Rumex alpinusexhibited higher N and P contents in emerging and mature leaves than in the senescent compared to Ca and Mg. The N:P and N:K ratios in the mature leaves were within the normal range but were indicative of comparatively higher demand for P. The mean resorption efficiency for N, P, and K was 52, 50, and 22%, respectively, lower than values for most terrestrial plants (62, 65, and 70%). The relatively high availability of macroelements in soils and plant organs with low N, P, and K resorption efficiency indicates a high N, P, and especially K-demanding species of Rumex alpinus.