| Indigofera amblyantha is the main shrub used in ecological restoration such as highways and metal-polluted soil remediation.The hardness of seed coat is the main reason for the low germination rate and inconsistent emergence of seedlings of I.amblyantha,which seriously affects the production and application of I.amblyantha.In this experiment,we evaluated the germination habit of 10 I.amblyantha seeds from different sources,the effects of different treatments on the seed germination and seedling growth of I.amblyantha,and the effects of acid,aluminum,salt-alkali and heavy metal treatments on the physiological characteristics of I.amblyantha seedlings,in order to screen out effective measures to improve the germination ability of I.amblyantha seeds,as well as to clarify the physiological response of I.amblyantha seedlings to acid aluminum,saline-alkali and heavy metals,and provide theoretical basis and practical guidance for the application of I.amblyantha in ecological restoration.The main results are as follows:(1)The shape of the seeds of I.amblyantha is oval,the color is dark green to black,light green to yellow,brown or dark green.There are differences in the clarity,moisture,thousand-grain weight and density of the seeds of I.amblyantha from different sources.The hardness rate of seeds is I-3(56.00%),and the I-10 seed is the lowest(1.67%).(2)The germination characteristics of I.amblyantha seeds from different sources are obviously different.The germination rate of I-10 seed are the highest and the I-7 seed is the lowest.The germination ability of the seeds gradually decreased with the extension of storage time.After 8 months of storage,most of the seeds had lost their vigor.The storability of seeds varies among the different germplasm resources,and the I-9 had the highest germination rate after 8 months of storage.(3)For the I-3 seed with the highest hard seed rate,75% sulfuric acid treatment for 10 minutes is the best method to break the hardness of I.amblyantha seeds;piercing the seed coat in order to break the seed hardness caused seriously damages to the seeds;gibberellin treatment has no significant effects on seed germination;the most economical and practical method in production is 60℃ hot water treatment for 10-15 min.(4)For the I-9 seed,the stress treatments of different concentrations of aluminum solution,p H value of saline-alkali mixed solution,and cadmium solution inhibited the germination of the seeds of I.amblyantha.The aluminum ion stress above 1.48 mmol/L significantly inhibited the germination of I.amblyantha seeds.The salt-alkali stress between pH 8.8 and 9.4 had no significant effect on the germination of I.amblyantha seeds.p H values above 10.1 significantly inhibited the germination and seedlings growth.The cadmium solution with concentration of cadmium ion under 140 μmol/L promoted the seedling growth of I.amblyantha,and the solution with cadmium ion above 270 μmol/L inhibited the germination and seedling growth of I.amblyantha.(5)For I-9 seedling,high-concentration aluminum ion(above 2.96 mmol/L),salinealkali stress(above p H 10.1),and cadmium ion(above 540 μmol/L)significantly affected the antioxidant enzyme system of I.amblyantha,photosynthetic system,and the plasma membrane permeability of the cell,and as the stress time increases,the stress degree increases. |
