RESUMO
Cucumber is a warm climate vegetable that is sensitive to chilling reactions. Chilling can occur at any period of cucumber growth and development and seriously affects the yield and quality of cucumber. Hydrogen (H2) is a type of antioxidant that plays a critical role in plant development and the response to stress. Hydrogen-rich water (HRW) is the main way to use exogenous hydrogen. This study explored the role and mechanism of HRW in the cucumber defense response to chilling stress. The research results showed that applying 50% saturated HRW to the roots of cucumber seedlings relieved the damage caused by chilling stress. The growth and development indicators, such as plant height, stem diameter, leaf area, dry weight, fresh weight, and root length, increased under the HRW treatment. Photosynthetic efficiency, chlorophyll content, and Fv/Fm also improved and reduced energy dissipation. In addition, after HRW treatment, the REC and MDA content were decreased, and membrane lipid damage was reduced. NBT and DAB staining results showed that the color was lighter, and the area was smaller under HRW treatment. Additionally, the contents of O2- and H2O2 also decreased. Under chilling stress, the application of HRW increased the activity of the antioxidases SOD, CAT, POD, GR, and APX and improved the expression of the SOD, CAT, POD, GR, and APX antioxidase genes. The GSSG content was reduced, and the GSH content was increased. In addition, the ASA content also increased. Therefore, exogenous HRW is an effective measure for cucumber to respond to chilling stress.
Assuntos
Cucumis sativus , Cucumis sativus/metabolismo , Peróxido de Hidrogênio/metabolismo , Antioxidantes/metabolismo , Hidrogênio/metabolismo , Água/metabolismo , Superóxido Dismutase/metabolismo , Plântula/metabolismoRESUMO
Our aim is to evaluate the safety and efficacy of tunneled dialysis catheter (TDC) exchange through fibrin sheath crevice vs in situ catheter exchange in hemodialysis patients with fibrin-sheath-related catheter dysfunction. Patients with fibrin-sheath-related catheter dysfunction who underwent TDC exchange in our center between 2012 January and 2017 December were retrospectively screened. The included patients were divided into the sheath-crevice group (catheter was exchanged through fibrin sheath crevice) and the in situ group (catheter was exchanged in situ). The blood volume, Kt/V values, and complications were assessed as outcomes. Of the 44 included patients, 25 underwent in situ catheter exchange and 19 underwent catheter exchange through the fibrin sheath crevice. The stabilized maximal blood flow during the first hemodialysis after the catheter replacement reached 250 mL/min in all of the included patients. After 3 months, the stabilized maximal blood flow of the in situ group and the sheath-crevice group were 245.3 ± 9.0 and 244.8 ± 10.05 mL/min (P = .963), respectively. However, after 6 months, the stabilized maximal blood flow during hemodialysis (P = .048) and the Kt/V value (P < .001) of the patients in the sheath-crevice group were significantly higher than the in situ group. No severe complication related to the catheter exchange surgery was observed in either group. For patients with TDC dysfunction caused by fibrin sheath, catheter exchange through the fibrin sheath crevice most likely is a safe and effective alternative strategy for in situ catheter exchange.