In vitro effects of CaO nanoparticles on Triticale callus exposed to short and long-term salt stress.

KEY MESSAGE: Ca2+ NPs enhanced tolerance of Triticale callus under salt stress by improving biochemical activity and confocal laser scanning analysis, conferring salt tolerance on callus cells. CaO NPs (Ca2+) are significant components that act as transducers in many adaptive and developmental processes in plants. In this study, effect of Ca2+ NPs on the response and regulation of the protective system in Triticale callus under short and long-salt treatments was investigated. The activation of Ca2+ NPs was induced by salt stress in callus of Triticale cultivars. MDA, H2O2, POD, and protein activities were determined in callus tissues. Concerning MDA, H2O2, protein activities, it was found that the Ca2+ NPs treatment was significant, and it demonstrated a high correlation with the tolerance levels of cultivars. Tatlıcak cultivar was detected for better MDA activities in the short time with 1.5 ppm Ca2+ NPs concentration of 50 g and 100 g NaCl. Similarly, the same cultivar responded with better H2O2 activity at 1.5 ppm Ca2+ NPs 100 g NaCl in the short time. POD activities exhibited a decreasing trend in response to the increasing concentrations of Ca2+ NPs. The best result was observed at 1.5 ppm Ca2+ NPs 100 g NaCl in the short term. Based on the protein content, treatment of short-term cultured callus cells with 1.5 ppm Ca2+ NPs inhibited stress response and it significantly promoted Ca2+ NPs signals as compared to control callus. Confocal laser scanning analysis proved that the application of Ca2+ NPs could alleviate the adverse effects of salt stress by the inhibition of stress severity in callus cells. This study demonstrated, under in vitro conditions, that the application of Ca2+ NPs can significantly suppress the adverse effects of salt stress on Triticale callus; it was also verified that the concentration of Ca2+ NPs could be important parameter to be considered in adjusting the micronutrient content in the media for this plant.