Mechanisms of Plant Tolerance to Heavy Metals Mediated by Gibberellic Acid

Heavy metals are toxic to most plants and severely interfere with their physiological metabolism. Some adaptive mechanisms, including improved antioxidant response, enhanced photosynthesis rate, adjusted metabolism rate and metal compartmentalization, have been evolved to alleviate the stress of heavy metals. As a classical hormone for regulating the growth and development of plants, gibberellic acid (GA) can enhance the plant tolerance to and uptake of heavy metals. This review summarizes the mechanisms of plant tolerance to heavy metals mediated by gibberellic acid, with an emphasis on plant biomass improvement, antioxidation, remediation of photosynthetic system, metal compartmentalization and signal communication. The future prospects, including the biosynthesis, decomposition as well as regulated roles of GA under heavy metal stress, the in-depth mechanisms of enhanced plant tolerance by GA, and the effects of GA application on phytoremediaiton efficiency, are also proposed.