Figure 1.
Effect of cultivating Echinacea purpurea in soils containing different levels of organic matter on in vitro macrophage stimulatory activity and bacterial load of the plant material. Soil with five different levels of organic matter (determined gravimetrically after combustion) was used. E. purpurea seedlings were grown in pots for five months, with six pots with three plants per pot, for each soil type. Dried roots (A) and aerial (C) material were extracted with 4% SDS and extracts evaluated for activity (macrophage TNF-alpha production, expressed as EC10 values). Total bacterial load (B,D) represents cells per gram of dried plant material. Bars represent mean values ± standard error. Treatments with different letters are significantly different (p < 0.05).