Effects of pericarp, storage conditions, seed weight, substrate moisture content, light, GA3 and KNO3 on germination of Euptelea pleiospermum

Euptelea pleiospermum is a rare tertiary relict tree species restricted to mountain riparian forests in China, India and Burma. Poor seedling recruitment is a serious threat to this species, but little is known about its seed or fruit germination. We examined the effects of pericarp, storage conditions, seed weight, substrate moisture content, gibberellic acid (GA3) and light regime, and potassium nitrate (KNO3) on seed or fruit germination. The final germination percentage was 0.8% for untreated fruits, reaching up to 21.2% for fruits with four months cold treatment. Germination test of fruits collected in four consecutive years revealed that seed vigour lost rapidly after one year. Both seed weight and GA3 had no significant effects on final germination percentage and germination dynamics. Pericarp prolonged the germination process, but it did not affect final germination percentage. The optimal substrate moisture content for germination was 20%. Light played a positive role in fruit germination. Nitrate combined with cold treatment were proven having an important effect on breaking non-deep dormancy in E. pleiospermum.