One aspect of the disclosure is directed to a method for activation/enhancement of cell growth of a plant. The method also stimulates the production of pharmaceutically active metabolites, including alkaloids, in plant cell cultures. The method includes providing a nano-sized material contained agent, and treating the plant with the nano-sized material contained agent to allow sufficient interaction of cells of the plant with the nano-sized material so as to activate/enhance the cell growth of the plant or to stimulate the production of pharmaceutically active metabolites.
