Effects of melatonin soaking on pepper seed germination and seeding drought resistance

MA Zhonglian; ZHOU Lingyu; CHEN Yue; HUANG Xianmin; MA Yongcui; SHI Zhilong

doi:10.1686l/j.cnki.zggc.202423.0772

Abstract：To improve the drought tolerance of pepper seeds and seedlings,0(CK),50 μmol·L-1(T1),100 μmol·L-1(T2),200 μmol·L-1(T3)melatonin solution and 15％polyethylene glycol(PEG 6000)to simulate drought were set up,with Guinong Changxianwang as the experimental material to study the effect of melatonin on the germination characteris-tics of pepper seeds and drought resistance of seedlings under drought stress.The results showed that melatonin treatment could effectively increase the germination rate of pepper seeds by 9.06-9.96 percentage points and seedling survival rate by 4.69-5.78 percentage points,and promote the growth of pepper seedlings compared with CK treatment.Under drought stress,compared with CK treatment,melatonin treatment could effectively increase leaf water retention capacity by 14.06-22.74 percentage points,hydroxyl free radical scavenging capacity by 3.95％-57.89％,and total antioxidant capacity by 23.73％-38.98％,and reduce cell membrane permeability by 12.96％-22.24％,malondialdehyde content by 9.12％-30.76％,and hydrogen peroxide content by 5.90％-20.85％.However,melatonin treatment significantly reduced solu-ble sugar content by 63.05％-77.61％and proline content by 4.43％-62.14％compared with CK treatment.Grey correlation analysis showed that melatonin mainly improved drought resistance of pepper seedlings by increasing underground biomass,total antioxidant capacity and relative leaf water content.The analysis of drought resistance coefficient showed that the av-erage drought resistance coefficient of T1,T2 and T3 were 1.09,1.22 and 1.05,respectively,with T2 having the strongest drought resistance.The comprehensive evaluation values of CK,T1,T2 and T3 treatments were 0.338 0,0.606 7,0.770 0 and 0.545 6.In summary,seed soaking with melatonin could improve the germination and growth characteristics of pepper seeds.Under drought stress,melatonin(100 μmol·L-1)treatment had the best effect on drought resistance of pepper.