Exogenous foliar spray of selenium (Se) alleviates cold stress by promoting photosynthesis and antioxidant defense in waxy maize

Abstract

Abstract Exogenous application of selenium (Se) is an effective approach to improve abiotic stresses under climate change scenario. To investigate the effects of Se-induced improvement of cold tolerance, waxy maize seedlings sprayed with varied Se dose (0, 30, 60, 90 mg L -1 ) were exposed to low temperature (13 °C, LT) and ambient temperature (25 °C, NT) for ten days. The plant growth performances, such as net photosynthetic rate (A n ), oxidative damage, enzymes activities and related gene expression, and non-enzymatic levels of AsA and GSH were evaluated. The results showed that LT induced higher levels of hydrogen peroxide (H 2 O 2) , superoxide (O 2 •−), and decreased membrane stability index (MSI), An, leaf area (LA) and shoot dry weight (SDW) compared to NT, while Se-sprayed plants displayed higher antioxidant enzymes activities of SOD, CAT, APX and GR, and up-granulated genes encoding these four proteins, as well the increased contents of AsA, GSH and GSH+GSSG under LT, thereby decreased the accumulation of H 2 O 2 and O 2 •− content, which in turn maintained higher MSI, An and subsequent SDW. The results indicated that Se-induced low temperature tolerance might be associated the improved photosynthetic capacity, as well as enhanced antioxidant defense system.