University of Tabriz Journal of Plant Physiology and Breeding 2008-5168 10 1 2020 06 01 The effects of titanium dioxide nanoparticles and spermine on physiological responses of licorice (Glycyrrhiza glabra L.) to cold stress اثرات نانوذرات دی اکسید تیتانیوم و اسپرمین بر پاسخ های فیزیولوژیکی گیاه شیرین بیان به تنش سرما 93 110 12557 10.22034/jppb.2020.12557 EN Vahideh Kardavan Ghabel Department of Biology, Faculty of Science, Bu-Ali Sna University, Hamedan, Iran. Roya Karamian Department of Biology, Faculty of Science, Bu-Ali Sina University, Hamedan, Iran. Journal Article 2020 03 19 Cold stress induces biochemical and physiological changes in plants. Therefore, it is important to identify and apply compounds that can increase plant tolerance to cold. Nowadays, the use of nanoparticles as a suitable solution to increase plant resistance to environmental stresses is considered. In addition, polyamines play an important role in regulating plant defense responses to environmental stresses. The aim of this study is to investigate the effects of spermine and titanium dioxide nanoparticles (TiO2 NPs) on physiological responses of licorice (Glycyrrhiza glabra L.) plants to cold stress. Results showed that cold stress increased the content of total protein, phenolic compounds, glycine betaine, soluble sugars, glycyrrhizin, proline, hydrogen peroxide and malondialdehyde and also the activity of antioxidant enzymes, but decreased photosynthetic pigments content and growth indices. Spermine increased most of the features measured at low temperature, but decreased the content of hydrogen peroxide and malondialdehyde. The production of glycyrrhizin was stimulated by cold stress and also application of spermine and TiO2 NPs. The use of TiO2 NPs and spermine alleviate the negative effects of cold stress and improved licorice plant responses. https://breeding.tabrizu.ac.ir/article_12557_7016da010aa27a44f52cf38a4c3a0ea8.pdf