2.3 Germination experiment
All seeds were surface sterilized by soaking in 0.5% sodium hypochlorite solution for 10 min and rinsed several times with distilled water. Five replicates of 50 seeds were placed in Petri dishes (90×15 mm) lined with 2-layer filter paper. The seeds and filter paper were wetted with 3 mL distilled water or extract solution. To maintain moisture, the Petri dishes were put in plastic bags and placed in a growth chamber at temperature of 20/16°C for 12/12 h in light and dark period. The light intensity was 3000 lux. A seed was considered germinated when the root protruded ≥2 mm. Germination was counted at 24 h intervals over 15 days, and the first count was carried out on the fourth day.
2.4 Seedling growth experiment
To evaluate the effects of different extracts on seedling growth, a completely randomized block design with three replications was applied to conduct seedling growth tests on growth plate (5×8 cups; Ø 40 mm; height 80 mm). The media was a mixture vermiculite/pearlite (50:50, v/v). Three pre-germinated seeds (5 days old) were transplanted into each cup, and ten cups were used as a replicate. The growth plates were place in growth chambers with temperature of 20/16°C for 12/12 h in light and dark period. The light intensity was 3000 lux. The moisture content of the media was maintained at a ratio of 1.5:1 solution or water to media on weight basis by spraying different plant extracts every three days. After 10 days of growth, the seedling with roots were carefully washed from media. Ten seedlings of a replicate were selected and the plumule length and radical length of each seedling were measured. The seedlings were oven-dried to constant weight at 65°C and weighed to obtain dry weights (mg·10 plants-1).