Pollen biological characteristics and breeding system of Primulina guizhongensis

[Objective] This paper aims to investigate the characteristics of Primulina guizhongensis pollen and the influence of the breeding system on its sexual reproduction, to uncover its reproduction mechanism and providing theoretical references for the conservation and development of Primulina. [Methods] Using P . guizhongensis as the material, we observed the floral characteristics of P . guizhongensis, screened the pollen isolation medium and the best pollen viability detection method, explored optimal pollen storage conditions, as well as determined the type of its breeding system. [Results] (1) P . guizhongensis was dichogamy, with stamens ripening before pistils. It was herkogamy, with pistils higher than stamens. (2) The optimum medium for culture of the isolated pollen germination was 40 mg/mL boric acid + 10% sucrose + 7 g/L agar, for two hours. (3) Pollen maintained a high germination rate after 7 d of storage at both -20 ℃ and -80 ℃. (4) The stigmas of P . guizhongensis were most fertile at 2-4 d of flowering. (5) P/O was 518.36-782.75, and OCI was 5. (6) P . guizhongensis had a high self-fertilization affinity and was unable to undergo fusionless reproduction. [Conclusion] In vitro germination method is the most intuitive and accurate way to detect pollen viability. Low temperature is conducive to pollen storage of P . guizhongensis, and the breeding system is predominantly heterogametic.