Study On The Influencing Factors Of Seed Germination Of Dioscorea Nipponica

In recent years,the demand for diosgenin has been increased dramatically.Planting is an effective way to protect wild resource.In this paper,an indoor-incubator experiment was carried out including environmental factors(light,temperature and moisture),growth regulators and endogenous substances to determine their effects to the germination of Dioscorea nipponica.Meanwhile,change rules of stored substance contents and enzyme activity with seed germination were analyzed.The results were as follows1.The interaction of temperature and water had no significant effect on seed germination rate and germination potential,but had very significant effect on relative germination index.Temperature had significant effect on seed germination rate and relative germination index.Germination rate and relative germination index at 25? and 30? were significantly higher than those at 20?.The effect of light on seed germination potential was significant.24h light treatment was beneficial to seed germination2.NAA had a significant effect on seed germination index of Dioscorea nipponica,but had no significant effect on germination rate and germinating potential of Dioscorea nipponica.But 6-BA and GA had no significant effect on the germination of Dioscorea nipponica.3.The water extract of seed of Dioscorea nipponica had no obvious inhibiting effect on the germination of Dioscorea nipponica.There was abscisic acid(endogenous inhibitor)in the seed.The amount of abscisic acid was 0.0427mg·g-1 in seed coat(including seed embryo),and 0.0009mg·g-1 in seed wing4.With the germination,the content of soluble protein decreased,the lowest content is 0.12 mg·g-1.The content of reducing sugar increased to the highest of 0.10 mg·g-1 at the true-leave stage.Content of starch and soluble sugar in seeds were increased from the seed-swelling stage to the seed-coat-rupture stage,while both of contents were decreased when the radicle exposed,and contents of soluble sugar was increased at the plantule-exposing and true-leaf stage.Content of starch was increased firstly and then decreased5.The activity of peroxidase(POD)was increased sharply from the seed-swelling stage to the seed-coat-rupture stage,up to 41.62 U·g-1.POD activity was decreased from seed-coatrupture stage to radicle-exposing stage,and then POD activity was gradually stable.