Growth Responses of Indonesian Foxtail Millet (Setaria italica (L.) Beauv.) to Cadmium Stress

Cadmium (Cd) contamination is considered as one of the most important environmental and human health issues worldwide. The occurrence of Cd in air, water and soil is resulted from massive industrialization, uncontrolled agricultural system and anthropogenic activities in urban lives. The presence of Cd in soil threatens human health through food chain bioaccumulation, negatively affect soil quality and also reduce the productivity of agricultural crops. Foxtail millet (Setaria italica L.) is an alternative cereal food that is highly tolerant to abiotic stresses such as drought and salinity. However, the mechanism underlying its response to the stress caused by heavy metals, such as Cd, remains unclear. This study aimed to examine the effects of Cd stress on morpho-physiological responses of the foxtail millet accession Buru Merah, cultivated using the hydroponic method. To this end, four levels of Cd concentrations (0, 0.5, 1.0, and 1.5 µM in ABmix™ growth media) were applied for 4 weeks followed by morpho-physiological assessements, including plant height, root length, shoot and leaf number, panicle biomass measurements and chlorophyll content evaluation. Our results demonstrated that Cd stress perturbed the growth of foxtail millet on morpho-physiological parameters, particularly at the highest Cd concentration (1.5 µM). The negative effects of Cd stress included decrease in shoot length, root length, number of leaves and shoots, panicle biomass, and chlorophyll content. Furthermore, our findings showed that Cd stress affected the growth of foxtail millet in a concentration-dependent manner. Taken together, our findings might be useful for further development of strategies to increase plant tolerance to heavy metal stress and ensure sustainable food production. In addition, this study also demonstrated the importance of protecting nature from Cd contamination.