Abstract:

The objective of this paper is to study the flower morphological structure and flowering characteristics of Fraxinus, and to provide a theoretical basis for its pollination and fertilization. In this paper, three varieties of Fraxinus (‘Lu la No.2’, ‘Lu la No.5’ and ‘Jinjian’) were selected to observe their flowering characteristics and morphological structure of flower. The results show that the flowering period of male plants of Fraxinus is 11-13 days, which is 13-15 days earlier than that of female plants. The flowering period of the female plants of ‘Lu la No. 2’ is only 5-6 days. The small flowers of the 3 Fraxinus varieties are dense without corolla. Their bracts become 2 lobes after flowering, and the calyx is bell-shaped with 4 deep lobes. The male flowers reveal boat-shaped anthers and extremely short filaments accompanying their blooming. The female flower reveals the pistils after its bracts are cracked and its stigma is split into two at maturity and becomes pink, and its peduncle is extremely short. Shield hairs are observed on the bracts and calyx surface of the three Fraxinus varieties under scanning electron microscope, and the morphology of shield hairs differs between different varieties. The anther and pollen structure are not significantly different between ‘Jinjian’ and ‘Lu la No.5’. There are significantly irregular folds on the entire pistil surface of ‘Lu la No.2’. The study lays a foundation for further research on the breeding of Fraxinus and the innovative utilization of Fraxinus germplasm resources.

Key words: Fraxinus, flower organ, flowering characteristics, scanning electron microscope