Morphological and anatomical changes during dormancy break of the seeds of Fritillaria taipaiensis.

Fritillaria taipaiensis P. Y. Li is the most suitable species planted at low altitudes among other species used as Tendrilleaf Fritillary Bulb, whose seeds embracing the morphological and physiological dormancy need to experience a long-dormant time from sowing to germination. In this study, the developmental changes of F. taipaiensis seeds during dormancy period were observed by morphological and anatomical observation, and the cause of long-term dormancy of seeds was discussed from the perspective of embryonic development. The process of embryonic organogenesis was revealed during the dormancy stage by the paraffin section. The effects of testa, endosperm and temperature on dormant seeds were discussed. Furthermore, we found that the mainly dormant reason was caused by the morphological dormancy, which accounted for 86% of seed development time. The differentiation time of the globular or pear-shaped embryo into a short-rod embryo was longer, which was one of the chief reasons for the morphological dormancy and played an important role in embryonic formation. Testa and endosperm with mechanical constraint and inhibitors involved in the dormancy of F. taipaiensis seeds. The seeds of F. taipaiensis, the average ambient temperature of 6-12°C for morphological dormancy and 11-22°C for physiological dormancy, were unsuitable for seed growth. Therefore, we suggested that the dormancy time of F. taipaiensis seeds could be shortened by shortening the development time of the proembryo stage and stratification for the different stages of dormancy.