Response to temperature stress of reactive oxygen species scavenging enzymes in the cross-tolerance of barley seed germination.
A number of studies have shown the existence of cross-tolerance in plants, but the physiological mechanism is poorly understood. In this study, we used the germination of barley seeds as a system to investigate the cross-tolerance of low-temperature pretreatment to high-temperature stress and the possible involvement of reactive oxygen species (ROS) scavenging enzymes in the cross-tolerance. After pretreatment at 0 °C for different periods of time, barley seeds were germinated at 35 °C, and the content of malondialdehyde (MDA) and the activities of ROS scavenging enzymes were measured by a spectrophotometer analysis. The results showed that barley seed germinated very poorly at 35 °C, and this inhibitive effect could be overcome by pretreatment at 0 °C. The MDA content varied, depending on the temperature at which seeds germinated, while barley seeds pretreated at 0 °C did not change the MDA content. Compared with seeds germinated directly at 35 °C, the seeds pretreated first at 0 °C and then germinated at 35 °C had markedly increased activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR). The SOD and APX activities of seeds germinated at 35 °C after 0 °C-pretreatment were even substantially higher than those at 25 °C, and GR activity was similar to that at 25 °C, at which the highest germination performance of barley seeds was achieved. These results indicate that low-temperature pretreatment can markedly increase the tolerance of barley seed to high temperature during germination, this being related to the increase in ROS scavenging enzyme activity. This may provide a new method for increasing seed germination under stress environments, and may be an excellent model system for the study of cross-tolerance.
Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Yu-qin
YQ
Mei
Song-quan
SQ
Song
D060387:Ascorbate Peroxidases; D002374:Catalase / Q000378:metabolism; D018525:Germination; D005980:Glutathione Reductase / Q000378:metabolism; D001467:Hordeum / Q000201:enzymology* / Q000502:physiology; D008315:Malondialdehyde / Q000032:analysis; D010544:Peroxidases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism; D013696:Temperature
D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase