极小种群野生植物舟柄铁线莲种子萌发特性研究OA

[Objective]This study aims to explore the reasons for dormancy of Clematis dilatata seeds and find effective methods to break dormancy,providing a basis for the protection,development and utilization of this plant.[Method]Using seeds of C.dilatata as experimental material,the morphological traits,seed coat permeability,and endogenous inhibitors(using seeds of Brassica rapa var.glabra as the receptor)were observed.Furthermore,treatments with different gibberellin(GA3)concentrations(0,50,100,and 200 mg·L-1)were applied,varying durations of cold stratification(0-98 d),and treatments of different temperature(constant and alternating)and photoperiod(alternating light/dark and complete darkness)were combined to screen for the m ost effective dormancy-breaking method.[Result]At maturity,seeds of C.dilatata had differentiated but underdeveloped embryos.The seed coat showed good water permeability,posing no barrier to water uptake by the embryo.Aqueous extracts from the seed coat and endosperm had no significant effect on the germination of B.rapa var.glabra seeds.Compared to the constant temperature(25℃)or complete darkness,alternating temperature(25℃16 h/15℃8 h)and a light/dark cycle(light 16 h/dark 8 h)were more conducive to seed germination.Cold stratification significantly reduced the mean time to radicle emergence(21-45 d)compared to the control(75 d).When stratification duration increased,germination rate firstly increased and then decreased,while germination potential firstly increased and then stabilized,and the mean time to radicle emergence decreased progressively until stabilizing.After 70 d of cold stratification,germination rate peaked at(64.33±5.51)%,with a germination potential of(7.33±1.15)%and a mean radicle emergence time of 25 d.Treatment with 50 mg·L-1 GA3 resulted in a high germination rate of(68.33±3.51)%,a germination potential of(8.00±1.00)%,and a mean radicle emergence time of 23 d.However,higher GA3 concentration reduced both germination rate and potential,and prolonged the mean time to radicle emergence.[Conclusion]Seeds of C.dilatata belong to non-deep simple morphophysiological dormancy.Under alternating temperature and light/dark conditions,treatment with 50 mg·L-1 GA3 or cold stratification for 70 d can effectively seed dormancy.