外源咖啡酸处理对中国沙棘种子萌发的影响OA

To investigate the optimal concentration and underlying mechanism of exogenous caffeic acid on seed germination of Hippophae rhamnoides subsp.Sinensis Rousi,seeds collected from Xinglong Mountain were treated with different concen-trations(0,25,50,100,200,400 mg/L)of caffeic acid.The results showed that exogenous caffeic acid exhibited low-concentration promotion and high-concentration inhibition effect on seed germination.Low concentrations(25 mg/L and 50 mg/L)promoted germination during the critical period(days 5 to 7).The 25 mg/L treatment yielded the highest germination potential on day 5,with notable improvements in germination uniformity and radicle growth.The 50 mg/L treatment simulta-neously increased germination rate,germination potential,and fresh weight,while reducing the mean germination time.Both concentrations activated the antioxidant system,enhanced peroxidase activity,and maintained low malondialdehyde content.High concentrations(200 mg/L and 400 mg/L)inhibited seed germination,leading to a comprehensive decline in key germi-nation indices,suppressed peroxidase activity,and a sharp increase in malondialdehyde content.Except for the 50 mg/L treatment on day 6,which showed a significant difference from the control,no significant effects on seed dry weight were ob-served for other treatments.In conclusion,exogenous caffeic acid at concentrations of 25 mg/L and 50 mg/L promoted seed germination by enhancing antioxidant activity and alleviating oxidative damage,providing a basis for the application of exog-enous chemicals in seabuckthorn seedling cultivation.