Selenium biofortified Aechmea blanchetiana (Bromeliaceae) can resist lead-induced toxicity during in vitro culture

Lead (Pb) is a heavy metal that can induce morphophysiological changes and disturb the normal functioning of plants. However, the deleterious effects caused by exposure to heavy metals can be alleviated by co-exposure to some mineral elements such as selenium (Se). We analyzed the morphophysiological changes of Aechmea blanchetiana in response to Pb and Se co-exposure during in vitro growth. First, the plants were cultured in media containing 0 or 4 µM Se. After 72 days of culture with both Se treatments, a sterilized solution containing Pb in a concentration gradient (0, 500, 1000, or 2000 µM) was added, forming a two-phase medium with eight treatments. At 75 days of Se and Pb treatment, the changes in physiology and anatomy of the plants were verified. The number and diameter of xylem vessels of the leaves decreased with rising Pb concentrations. Plants grown without Se and supplemented with Pb presented characteristics of stress, such as lower content of photosynthetic pigments, magnesium and manganese, and lower RC/CS M . In contrast, plants cultured with Se had higher pigment content and better performance of photosynthetic apparatus, as confirmed by the negative K- and L-bands and PI (Total) values. Both Pb and Se alone and their combined use affected the growth, physiology, and anatomy of A. blanchetiana plants. This species can be used as a bioindicator agent due to its bioaccumulation capacity and tolerance to excess Pb.