Effects of combined fluridone and gibberellin on the germination and emergence of Agriophyllum squarrosum seeds

Seed germination is key to successful natural regeneration of the pioneer plant Agriophyllum squarrosum in moving dunes. Additionally, it is an important factor restricting its artificial cultivation. Seeds collected in the current year were used to study the effects of different fluridone (FL) concentrations and soaking times, alone and in combination with gibberellin (GA₃), on seed germination and emergence and to screen for the FL + GA₃ combination that most effectively promoted seed germination and emergence. FL immersion effectively broke A. squarrosum seed dormancy, and the effects of FL concentration and duration of immersion on A. squarrosum seed germination rate were determined. The germination rate of A. squarrosum seeds increased gradually with increasing FL concentrations in the range of 0.1% to 10%. The germination rate increased gradually with increasing immersion times within a 3～24 h range, reaching its maximum with 24 h immersion. The optimal FL concentration was 5.0 μmol· L⁻¹, and the optimal soaking time was 24 h. Adding GA₃ to an FL solution synergistically enhanced emergence rates obtained with low FL concentrations and abrogated the high mortality rate of seedlings treated with FL alone. 5.0 μmol· L⁻¹ FL + 2.0 g · L⁻¹ GA₃ was optimal. This combination treatment increased the A. squarrosum seed germination rate and achieved the highest seedling preservation rate, which could provide a theoretical basis and technical support for the artificial cultivation of A. squarrosum in the field.