The role of beneficial elements in triggering adaptive responses to environmental stressors and improving plant performance

Abstract

Aluminum (Al), cerium (Ce), cobalt (Co), iodine (I), lanthanum (La), sodium (Na), selenium (Se), silicon (Si), titanium (Ti), and vanadium (V) are emerging as novel biostimulants that may enhance crop productivity and nutritional quality while improving responses to environmental stimuli and stressors in some plant species. These beneficial elements are not essential for most plants, but when supplied at low dosages, they help improve their growth, development, and yield quality by stimulating different molecular, biochemical, and physiological mechanisms triggering adaptive responses to challenging environments. When plants are exposed to environmental cues such as drought, heavy metal toxicity, low temperatures, saline soils, pest insects, or pathogens, beneficial elements may induce tolerance, resistance, or defense responses that allow plants to achieve acclimation to such stressors. Enhancement of nutrient uptake, synthesis of antioxidants and osmoprotectants, stimulation of secondary metabolism and signaling cascades, and reduction of senescence are among the responses boosted by beneficial elements when applied at low dosages. Nevertheless, beneficial elements may trigger hormesis in plants, a biphasic dose response with at low-dose stimulation or beneficial effect and a high-dose inhibitory or toxic effect. Thus, when properly applied, beneficial elements may have great potential to cope with some of the most daunting challenges facing humanity, such as climate change and food production under restrictive conditions for the growing human population. In this chapter, we mainly focus on the positive effects of beneficial elements on plant performance in restrictive environments and discuss some of the challenges of using these elements as biostimulants.