Tea plants and air pollutants

The major tea-growing regions of the world are located in Asia, where tea contributes substantially to their economy. It is known how the rapid development of the economy, twinned to global change, has created in many districts of industrialized countries critical levels of air pollution. Abiotic stresses may affect plant growth, quality, and distribution. This is particularly important for specialty crops such as tea, where functional quality is determined by phytonutrients, secondary metabolites, and bioactive components that play a pivotal role in plant defense and acclimation/adaptation/resilience to environmental stresses. Stress conditions such as drought, heat, light extremes, salinity, and toxic metals in the substrate have been the subject of intense researches, and the sensitivity of tea plants to these constraints has been tested by the scientific community through field and controlled experiments. Tea plants present high leaf surface areas, and exchange with atmosphere is elevated. However, little is known about the way air pollution affects tea responses and how this species is able to counteract this insult. In this chapter, the existing literature reporting the effects of air pollution on the tea plant is reviewed with the aim to examine physiological, biochemical, and molecular responses found in this species. To the best of our knowledge, only the impacts of few air pollutants have been somehow assessed on tea plants, and several responses are still poorly understood. Thus, more research on the impact of air pollution on tea plants is needed. This is of pivotal importance also because commercial tea samples may contain significant quantities of contaminants, which may be transferred to the consumer. No doubt that health national/international bodies should pay more attention to this issue and adopt safe standards of pollution content in the commodities of one of the world’s most popular beverages, highly appreciated also by young people because of its pleasant aroma, flavor, and potential positive effect on mood