Background: Cryopreservation is the best way for long-term in vitro preservation of plant germplasm resources. The preliminary studies found that reactive oxygen species (ROS) induced oxidative stress and ice-induced membrane damage are the fundamental causes of cell death in cryopreserved samples. How to improve plant cryopreservation survival rate is an important scientific issue in the cryobiology field. Results: This study found that the survival rate was significantly improved by adding single-wall carbon nanotubes (SWCNTs) to plant vitrification solution (PVS) in cryopreservation of Agapanthus praecox embryogenic callus (EC), and analyzed the oxidative response of cells during the control and SWCNTs-added cryopreservation protocol. The SWCNTs entered EC at the step of dehydration and mainly located around the cell wall and in the vesicles, and most of SWCNTs moved out of EC during the dilution step. Combination with physiological index and gene quantitative expression results, SWCNTs affect the ROS signal transduction and antioxidant system response during plant cryopreservation. The EC treated by SWCNTs had higher antioxidant levels, like POD, CAT, and GSH than the control group EC. The EC mainly depended on the AsA-GSH and GPX cycle to scavenge H₂O₂ in the control cryopreservation, but depended on CAT in the SWCNTs-added cryopreservation which lead to low levels of H₂O₂ and MDA. The elevated antioxidant level in dehydration by adding SWCNTs enhanced cells resistance to injury during cryopreservation. The ROS signals of EC were balanced and stable in the SWCNTs-added cryopreservation. Conclusions: The SWCNTs regulated oxidative stress responses of EC during the process and controlled oxidative damages by the maintenance of ROS homeostasis to achieve a high survival rate after cryopreservation. This study is the first to systematically describe the role of carbon nanomaterial in the regulation of plant oxidative stress response, and provided a novel insight into the application of nanomaterials in the field of cryobiology.

Lotus is an aquatic plant that is sensitive to water loss, but its seeds are longevous after seed embryo dehydration and maturation. The great difference between the responses of vegetative organs and seeds to dehydration is related to the special protective mechanism in embryos. In this study, tandem mass tags (TMT)-labeled proteomics and parallel reaction monitoring (PRM) technologies were used to obtain novel insights into the physiological regulatory networks during lotus seed dehydration process. Totally, 60,266 secondary spectra and 32,093 unique peptides were detected. A total of 5,477 proteins and 815 differentially expressed proteins (DEPs) were identified based on TMT data. Of these, 582 DEPs were continuously downregulated and 228 proteins were significantly up-regulated during the whole dehydration process. Bioinformatics and protein-protein interaction network analyses indicated that carbohydrate metabolism (including glycolysis/gluconeogenesis, galactose, starch and sucrose metabolism, pentose phosphate pathway, and cell wall organization), protein processing in ER, DNA repair, and antioxidative events had positive responses to lotus embryo dehydration. On the contrary, energy metabolism (metabolic pathway, photosynthesis, pyruvate metabolism, fatty acid biosynthesis) and secondary metabolism (terpenoid backbone, steroid, flavonoid biosynthesis) gradually become static status during lotus embryo water loss and maturation. Furthermore, non-enzymatic antioxidants and pentose phosphate pathway play major roles in antioxidant protection during dehydration process in lotus embryo. Abscisic acid (ABA) signaling and the accumulation of oligosaccharides, late embryogenesis abundant proteins, and heat shock proteins may be the key factors to ensure the continuous dehydration and storage tolerance of lotus seed embryo. Stress physiology detection showed that H₂O₂ was the main reactive oxygen species (ROS) component inducing oxidative stress damage, and glutathione and vitamin E acted as the major antioxidant to maintain the REDOX balance of lotus embryo during the dehydration process. These results provide new insights to reveal the physiological regulatory networks of the protective mechanism of embryo dehydration in lotus.

Florfenicol (FFC) is a commonly used antibiotic in animal husbandry, which is easy to cause organs damage in a variety of animals. It has been proved to have nephrotoxicity and affect the yield and quality of meat products. Salvia miltiorrhiza polysaccharides (SMPs) have been proved to have the pharmacological effects of regulating immunity and protecting the liver of animals, and its alleviative effect on renal injury is unclear. In order to investigate the alleviating effect of SMPs on drug nephrotoxicity and determine its potential molecular mechanism, we took chicks as the research object, FFC as the induced drug, and established the model by adding SMPs in drinking water. The chicks were randomly divided into control group, FFC model group (0.15 g/L FFC), FFC + low, medium and high dose of SMPs groups (0.15 g/L FFC + 1.25, 2.5, 5 g/L SMPs) and SMPs group (5 g/L SMPs). The results showed that, SMPs increased the average weight gain and renal index of chicks, alleviated the pathological changes of renal structure induced by FFC, decreased the contents of uric acid, blood urea nitrogen and creatinine in serum and malondialdehyde in renal tissue, increased the levels of glutathione, superoxide dismutase and catalase in renal tissue, up-regulated the relative expression levels of nuclear factor erythroid 2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase-1 (NQO-1) mRNA and protein, and down-regulated the relative expression levels of p53, Caspase-3 and Caspase-6 mRNA and protein and the apoptosis rate of renal histiocytes. It is concluded that SMPs could significantly alleviate the renal injury induced by FFC, and its mechanism may be related to improving renal antioxidant capacity and inhibiting abnormal apoptosis of renal histiocytes.