Ground-level ozone stress in medicinal plants: response mechanisms and adaptive strategies

Abstract

Ground-level ozone (O3) has strong oxidative properties and is a significant threat to the health of humans, animals, and plants. Currently, in comparison with studies on crops and horticultural plants, studies evaluating the impact of ozone stress on medicinal plants are relatively rare, and the methodologies employed are somewhat limited. Ozone stress can impact medicinal plant growth and reproduction at multiple levels, including the community, whole plant, and cellular levels, potentially leading to a decline in the quality of medicinal materials. This study systematically reviewed the effects of ground-level ozone on the phenotypic changes in the leaves, flowers, fruits, and seeds of medicinal plants, as well as its impact on harvest timing. Furthermore, a comprehensive analysis was carried out at the level of antioxidant defense, secondary metabolite production, gene regulatory networks, and symbiotic microbial interaction mechanisms. This review advocates the use of diverse research methods to enhance the effects of ozone stress on the active constituents of medicinal plants, considering the combined effects of ozone and other abiotic factors, such as drought, salinity, and high temperatures. It is imperative to elucidate the molecular regulatory mechanisms underlying the tolerance of various types of medicinal plants, including trees, shrubs, and herbaceous species, to develop targeted production management strategies against ozone stress. It also aims to clarify the impacts of ozone stress on medicinal plants and to offer insights for their cultivation and conservation efforts.