Physiological and phytochemical responses of three nutrient-stressed bulbous plants subjected to vermicompost leachate treatment

The role of vermicompost leachate (VCL) on growth, photosynthetic pigments, phytochemical content and the bioactivities of three bulbous (Eucomis autumnalis, Tulbaghia ludwigiana and Tulbaghia violacea) plants with medicinal and horticultural potential under nutrient-stressed conditions was evaluated. After 15 weeks, the nutrient-stressed plants were harvested and growth parameters were recorded. Spectrophotometric methods were used to quantify the photosynthetic and phytochemical contents. Harvested plant materials were extracted with 50 % methanol and subjected to antioxidant, acetylcholinesterase inhibitory (AChEI) and antifungal bioassays to elucidate the effect of the applied VCL under nutrient stress. While VCL did not significantly enhance growth of the three species, it significantly increased photosynthetic pigment content in 50 % Hoagland's-treated Eucomis autumnalis and in phosphorus-deficient Tulbaghia ludwigiana. Among the quantified phytochemicals, the most promising finding was the significant increase in condensed tannin and iridoid contents in VCL-supplemented-nutrient-stressed Tulbaghia violacea. Better antioxidant (Eucomis autumnalis) and AChEI (Eucomis autumnalis, Tulbaghia violacea) activities were detected when VCL was applied under nutrient stress. The current findings indicate that the application of VCL holds potential in cultivation of plants under nutrient-stressed conditions.