Study on nutrient stress tolerance of nine Taraxacum microspecies with a contrasting mineral ecology by cultivation in a low nutrient flowing solution

Growth and mineral status of 9 Taraxacum microspecies were studied under mineral stress conditions, using a flowing solution of low nutrient concentration. Relative growth rate of (whole) plant dry weight, leaf area, and (whole) plant tissue water were used to describe growth. For 4 microspecies, specific uptake rates of NO^?₃, H₂PO^?₄, K⁺, Mg²⁺ and Ca²⁺ were investigated.
The applied nutrient condition clearly discriminated between the studied Taraxacum microspecies. With respect to relative growth rate, 3 groups of microspecies could be distinguished: T. nordstedtii > T. lancidens, T. adamii, T. hollandicum, T. taeniatum > T. sellandii, T. eudontum, T. ekmanii, T. ancistrolobum . These categories coincided well with the mineral ecology of the microspecies, going from infertile to fertile sites.
T. nordstedtii , a microspecies of infertile sites, was most efficient in absorbing NO^?₃, H₂PO^?₄ and K⁺. T. sellandii and T. eudontum , both occurring in fertile grasslands, showed poor uptake performances for all studied ions. In all Taraxacum microspecies studied, except T. eudontum , internal N concentration appeared to limit growth. Efficiencies in N use, at sub-optimal internal N concentrations, varied with the mineral habitat of the microspecies studied. T. nordstedtii , from infertile sites, and T. sellandii , from fertile sites, were established as high and low extremes, respectively.