Growth responses of Urtica dioica to nutrient supply

Abstract

This study examines the effects of nutrient supply (three N–P–K treatments: 75, 225, and 375 kg∙ha−1; 12.5% N, 8.5% P, 16% K) on growth, allometry, and architecture of Urtica dioica L., an expansive clonal plant found throughout Central Europe. Biomass allocation was significantly affected by nutrient supply: higher nutrient doses resulted in less biomass allocation to belowground organs, whereas the period of intensive production of aboveground biomass was prolonged. Shoot height increases with nutrient supply. The height ratios were constant over time. Within each treatment and each harvest, inflorescence biomass was positively correlated with shoot height. Branching of the main shoots (number of lateral branches) was positively correlated with plant height and changed with time. The number of new rhizomes was affected by both treatment and harvest, especially in older plants. The results suggest that high nutrient supply increased the allocation of biomass both to reproductive organs and to vegetative organs. Key words: allometry, biomass allocation, clonal plant, nutrients, plant architecture, Urtica dioica.