Study on Seed Germination Characteristics of Endangered Tree Species Ormosia saxatilis in Guizhou Province

In order to explore the germination characteristics of Ormosia saxatilis seeds and limiting factors affecting seed germination, the physical properties and water absorption of Ormosia saxatilis seeds were measured, and two combinations of seed coat pretreatment and germination temperature treatment were carried out, and the methanol extracts of seed coat and embryo were measured by bioassay. The results showed that the seeds of Ormosia saxatilis were dormant, and the seed coat was hard and compact, less permeable breathability. Scratching the Ormosia saxatilis seed coat with a knife could effectively improve the permeability of the seed coat, and the cumulative water absorption rate in 96 h reached 63.63%, which was 60.56% higher than that of untreated seeds. The germination rate of peeled Ormosia saxatilis seeds was the highest, reaching 45.5%, which was 25.7% higher than that of non-peeled seeds. The germination of Ormosia saxatilis was limited by seed coat, and the combination of seed coat removal and temperature change at 25℃/20℃ had the best germination effect, with the gemination rate as high as 61.0%. The seed coat extract and embryo extract of Ormosia saxatilis could inhibit the gemination of Brassicca campestris seeds. With the increases of extract solution concentration, the germination inhibition rate gradually increased and the seed germination rate gradually decreased. The inhibitory effect of seed coat extract was significantly higher than that of embryo. Compared with the control, the germination rate of Brassicca campestris seeds treated with 0.01g·mL⁻¹, 0.05g·mL⁻¹ and 0.1g·mL⁻¹ seed coat methanol extract decreased by 20.0%, 42.0% and 64.0% respectively, and the germination inhibition rate increased by 25.6%, 53.9% and 84.6% respectively. It was preliminarily considered that the reasons for seed dormancy of Ormosia saxatilis was poor seed coat permeability, and the inhibitory substances contained in seed coat and embryo.