小苍兰幼苗对高温胁迫的生理响应

以小苍兰品种“上农金皇后”15 d幼苗为实验材料,测定其叶片在30℃高温胁迫144 h期间的生理指标变化.结果表明:高温胁迫期间,幼苗叶片中的叶绿素含量不断下降,胁迫结束时叶绿素含量显著低于对照；细胞膜透性(EL)、丙二醛(MDA)含量显著升高,脯氨酸随胁迫不断积累；可溶性糖含量在高温胁迫前6h里轻微下降,然后持续上升...

Physiological Responses of Freesia hybrida Seedlings to High Temperature Stress

Fifteen-day-old seedlings of Freesia hybrida Shangnong Jinhuanghou＇ were exposed to 30 ℃ for 144 h to investigate the physiological response to high temperature stress.The results showed that high temperature stress causes a significant decrease in chlorophylls content and a significant increase in malondialdehyde（MDA） content and electrolytic leakage（EL） in Freesia seedlings.Under high temperature stress,accumulation in proline content was observed,while a slight decrease in soluble sugar content occurred in the first 6 h exposure to stress,followed by a constant increase.Superoxide radical（O·-2） producing rate increases in the first 2 h exposure and then significantly decreases up to 72 h,followed by an increase at the end of stress.Antioxidant enzymes were triggered to scavenge reactive oxygen species（ROS） under high temperature stress.The change pattern of superoxide dismutase（SOD） activity is exactly contrary to that of O·-2 producing rate.SOD activity decreased in the first 2 h exposure,followed by a significant increase up to 72 h and then decreased at 144 h.Catalase（CAT） and peroxidase（POD） activities showed a similar change pattern：a significant increase after an early short-term decrease under high temperature stress.For ascorbate peroxidase（APX）,high temperature caused a constant increase and a significant higher level of APX activities than control in treated Freesia seedlings.These results provided further physiological basis for the Freesia cultivation,especially in high temperature regions.