Effects of supplementary nitrogen on biomass and nitrogen accumulation in the sundew Drosera capensis L.

The effect of nutrient supplementation on biomass and nitrogen accumulation in the insectivorous plant Drosera capensis L. was studied under laboratory conditions using supplementary feeding of ammonium chloride (Nr4CI) to plant leaf surfaces. The nitrogen solution used was based on a standard concentration of 157.6 mM NH4CI. Drosera capensis did not differ significantly in biomass or nitrogen accumulation from concentrations of 50%, 75%, 100%, 150%, or 200% of nutrient fertilizer when applied to the foliage. Reproductive structures were observed in higher numbers in those plants treated with higher concentrations of Nr4Cl but no relationship was found between reproductive structures and biomass or nitrogen concentrations. The results of this experiment potentially indicate that D. capensis can grow and initiate reproductive structures without additional nutrients above which already exist in the soil mixture. The results also suggest that D. capensis does not readily absorb NH4CI through its leaves.