Flowering phenology and pollen characteristics of cultivated populations of Paeonia ostii 'Feng dan' at different altitudes

: From a pollination biology standpoint, this study compared modifications in the flowering phenology, soluble sugar and protein content of pollen, antioxidant enzyme system, and storage traits of five cultivated populations of Paeonia ostii 'Feng dan' at various altitudes in Luoyang. The findings indicated that the first blooming phase was delayed at greater altitudes. There was a significant difference in the soluble sugar content of pollen between sites; and there was no discernible relationship between soluble sugar content and altitude. With increasing altitude, there is a tendency for soluble protein content to decrease. The activities of antioxidant enzymes in pollen from cultivated populations at varying altitudes showed SOD and POD enzyme activities generally increasing with decreasing temperature, whereas CAT enzymes showed divergent patterns. Differences existed in the storage time of pollen across populations at different altitudes, and pollen from higher altitudes appeared to be better adapted to low-temperature storage environments. The rate of decrease in pollen viability under dry storage at-74.7 degrees C was significantly lower than under other storage conditions. The comprehensive analysis concludes that the variations in 'Feng dan' cultivation populations within the same region at different altitude zones can be leveraged for cross-pollination among proximate populations, utilizing low-temperature dry pollen storage technology, with the aim of achieving abundant oil peony production.