| Abstract: | Physiological responses to low temperature were analyzed in a chilling-tolerant centipedegrass (Eremochloa ophiuroides) accession, Shao Guan (SG), in comparison to the commercial cultivar, Common. Lower levels of ion leakage and higher chlorophyll (Chl) concentration were observed in SG than in Common during chilling stress. The maximum photochemical efficiency, the actual photosystem II (PSII) efficiency, photochemical quenching efficiency, and net photosynthetic rate were decreased during chilling stress in both genotypes, with higher levels of these parameters shown by SG than Common. In addition, higher activities of superoxide dismutase (SOD), catalase (CAT), ascorbate-peroxidase (APX) and glutathione reductase (GR), and higher concentrations of ascorbic acid (AsA) and glutathione (GSH) were observed in SG than in Common. Moreover, higher concentrations of putrescine (Put), spermidine (Spd), and spermine (Spm) were observed in SG than in Common. Correlation analysis indicated that SOD, CAT, APX and GR activities, and AsA and GSH concentrations showed high correlation to Put, while APX, GR, and AsA concentrations were correlated to Spd. Exogenous Put or Spd increased antioxidant enzyme activities and chilling tolerance. The results suggested that polyamine-regulated antioxidants are important for chilling tolerance in centipedegrass and protect plants against chilling induced oxidative damage. |
