This study examined the phytotoxicity of the extract of Datura metel. It involved the planting of seeds of monocot, yellow maize (Zea mays) and a dicot, brown bean (Phaseolus vulgaris), growth and analysis of seedlings of the two plants.
              Seeds of Z. mays were collected at the Institute of Agricultural Research and Training (IAR&T), Ibadan and the seeds of P. vulgaris were collected at International Institute for Tropical Agriculture (IITA), Ibadan, Nigeria. The leaf of D. metel was collected. The plant was identified and authenticated (FHI 111862) at Forestry Research Institute of Nigeria (FRIN) Ibadan, Nigeria. The collected leaves were carefully washed under running tap water and air-dried at room temperature for four weeks. The dry leaves were milled into a fine powder and extracted. The phytotoxic potentials of the extract were evaluated using a standard method. At the end of the experiment, seedlings were harvested, stem and leaf were separately collected, and shoot length of seedlings was measured, and kept frozen for the estimation of total protein, soluble sugar, free amino acids, proline, and plant pigments.
The findings revealed that different concentrations of aqueous extract of the leaf of D. metel retarded the rate of germination of seeds, significantly inhibited the shoot length of P. vulgaris and Z. mays andreduced concentrations of chlorophyll, free amino acids, protein, sugar, and proline.
In conclusion, this study revealed that the extract exhibited a deleterious effect on germination, growth and biochemical parameters in seedlings of P. vulgaris and Z. mays.