Blue and far-red light modify the adaptation of Lemna minor L. to cadmium stress based on glutathione, phytochelatin, chemical element and free amino acid levels

Abstract

Light quality has been shown to modulate plant responses to abiotic stresses. Here we studied whether alterations in the light spectrum affect the adaptation of Lemna (L.) minor L to cadmium (Cd) by determining changes in plant growth, Cd uptake, phytochelatins, glutathione, chemical elements and free amino acids levels upon application of the heavy metal. . The plants were cultivated in white light (W) or in white light supplemented with blue (B) or far-red (Fr) light and treated with Cd. The Cd-uptake and the phytochelatin accumulation enabling Cd-chelation was much greater in W light compared to B and Fr light. B light and Cd induced the greatest accumulation of Na, K and certain free amino acids such as Gly and Ala which may form complexes with Cd. Fr light and Cd in turn resulted in the greatest cysteine and glutathione levels, which may contribute to the proper function of the redox-sensitive proteins. In summary, the greatest Cd-extraction capacity of L. minor can be reached in W light. In contrast, B and Fr light are appropriate for the reduction of Cd-uptake. In addition, B light improves the Cd tolerance through accumulation of Cd-complexing amino acids and Fr light may have such effect through its influence on the thiol-dependent redox environment of tissues.