Dynamic Changes in Endogenous Substances in Flowering Organs of Camellia drupifera during the Flowering Stage

Camellia drupifera is an important woody oil plant in South China, renowned for its seed oil that is rich in unsaturated fatty acids and possesses significant antioxidant, anti-cancer, and immune-enhancing properties. The low fruit-setting rate of C. drupifera is influenced by multiple factors, including flowering stage climate, flowering habits, pollination biology, soil conditions, and self-incompatibility. Among these, large-scale pure forest plantations are the primary cause of the low fruit-setting rate. Although previous studies have explored the impact of self-incompatibility on fruit-setting in C. drupifera, research on the dynamic changes of endogenous substances during the flowering stage in pure forest environments remains limited. Research findings indicate that tannase activity is relatively high in the pistils of C. drupifera, creating a favorable environment for pollen tube growth. Plant hormones such as indole-3-acetic acid (IAA), cytokinin (CTK), gibberellin (GA), and ethylene (ETH) regulate the development and aging of floral organs through complex interactions. Specifically, high levels of IAA in the pistil promote pollen tube growth, while changes in ETH and ABA are closely related to the aging of floral organs. Under oxidative stress conditions, high levels of H2O2 in the pistil may contribute to self-incompatibility. The activity of superoxide dismutase (SOD) in the floral organs during the flowering stage is significantly higher compared to peroxidase (POD) and catalase (CAT), highlighting the critical role of SOD in regulating oxidative stress during this stage. This study provides new insights into the changes in endogenous substances in the floral organs of C. drupifera during the flowering stage. It offers theoretical references for understanding its sexual reproduction process and for the application of plant growth regulators to improve fruit setting.