Dormancy mechanism and breaking methods for hard seeds of Sophora davidii

ObjectiveIn order to provide reference for the improvement of sowing and seedling technology,Sopho-ra davidii seeds were used as materials to explore their dormancy mechanism and dormancy release methods.MethodWater absorption of seed coat,embryo activity and embryo germination characteristics were tested to analyze the effects of seed coat and seed embryo on dormancy. The bioassay method was used to determine the activity of seed endogenous inhibitors. Dormancy breaking methods such as acid corrosion,alkali corrosion,hormone,boiling water and mechanical treatment were used to screen the best dormancy breaking methods.ResultAfter being removed the seed coat,S. davidii seeds were in complete imbibition within 2 d,while intact seeds reached saturation in 5 d. S. davidii seeds had a relatively high germination potential,with its embryo vitality of 73.5%. The germination rate of embryo with removed seed coat was the highest(72.99%),which was significantly higher than that of intact seeds and seeds only with embryos(P<0.05). Endosperm and embryo of S. davidii contained components that inhibited seed germination. Among which,50%concen-tration of endosperm extracts could reduce the germination rate of cabbage germination rate to 75.85%. When cutting seed coat to break dormancy,the germination rate of S. davidii reached 72.42%;the second optimal method was 98%concen-trated sulfuric acid+300.0 mg/L GA3 immersing for 12 h,and the germination rate was 57.41%.ConclusionThe water and air permeability of seed coat of S. davidii seeds and endogenous inhibitor of endosperm and embryo are the main fac-tors affecting dormancy of S.davidii. The dormancy breaking methods such as cutting skin coat by machine,98%concen-trated sulfuric acid(corrosion with acid)+300.0 mg/L GA3(hormone immersion)soaking for 12 h can release dormancy effi-ciently and improve seed germination rate,which can be applied in the hard seed seedling.