Abstract:

In this study, we examined the post-blooming pollen fertility of two cut tree peony varieties, Fengdan and Huangguan, focusing on its relationship among pollen micro-morphology, metabolism, and viability. We employed the chromosome squash technique to observe nuclear karyotypes, micrometer measurements for anther morphology, and scanning electron microscopy for pollen morphology. Additionally, we used liquid culture and spectrophotometry to assess pollen germination rates and related metabolic indicators. Our results indicated that Fengdan was a diploid karyotype and produced approximately 12.62 million rounded pollen grains per flower, characterized by three fissures and a deformity rate of 97.2%. This variety exhibited over 50% germination at a simulated temperature of 25 ℃. In contrast, Huangguan possessed a triploid karyotype with around 2.88 million abnormally shaped triangular pollen grains per flower, resulting in a zero of germination rate. Relative to Fengdan, Huangguan showed significant reductions in superoxide dismutase activity, ascorbic acid content, and soluble protein levels by 46.7%, 39.3%, and 31.8%, respectively. The abnormal pollen morphology and metabolic disorders in Huangguan likely contribute to its germination failure. Overall, Huangguan variety is characterized by low pollen quantity and viability, minimizing the risk of pollen contamination in cut flower arrangements.

Key words: tree peony, cut flower, chromosome ploidy, karyotyping, pollen vitality