Chapter 3: Physiological Responses of Plants to Environmental Lithium Pollution

Lithium (Li) is considered an emerging metal contaminant in the environment. To better prepare for the challenges to crop productivity from Li pollution, it is necessary to have a better understanding of the physiological basis/mechanisms of the responses of plants to Li stress. The overview presented here of the toxic effects of Li shows that different plants may exhibit variations in the relationship between Li bioaccumulation and the severity of growth inhibition and reduction in the contents of the different photosynthetic pigments. To deepen our understanding of how different plants respond to Li exposure, many studies have focussed on the increase in oxidative stress, which could cause damage to biomolecules, such as membrane lipids and proteins. These damages could be translated into growth inhibition effects and the loss of photosynthetic pigments. In addition, since various mineral nutrients, such as K, Ca and Mg, play vital roles in various metabolic reactions and pathways, alterations in mineral contents in plants exposed to Li could result in metabolic reprogramming leading to growth alterations. It is proposed here that gene expression changes, particularly those involved in plant hormone metabolism and transport as well as autophagy, could also underlie the physiological responses of plants to Li stress.