Subsequently, several different terms have been used, namely, "acquired physiological immunity", "resistance displacement", "plant immune function" and "induced system resistance."[3] Many forms of stimulus have been found to induce the plant to the virus, bacteria and fungi and other disease resistance including Mechanical factors (dry ice damage, electromagnetic, ultraviolet, and low temperature and high temperature treatment, etc.) Chemical factors (heavy metal salts, water, salicylic acid) and Biological factors (fungi, bacteria, viruses, and their metabolites).[4]