Objective To investigate the differences in phenology, floral characteristics, and endogenous substance dynamics during the flowering period between high-yielding (HY) and low-yielding (LY) Camellia drupifera trees growing under identical environmental conditions, in order to provide theoretical support and technical guidance for increasing the yield of C.drupifera.

Method The study focused on C.drupifera trees with significant differences in yield over consecutive years: high-yielding trees (High Yield, abbreviated as HY) and low-yielding trees (Low Yield, abbreviated as LY). A quantitative analysis was conducted to compare phenological changes, floral characteristics, pollination traits, pollen viability, polyamine levels, ROS, H₂O₂ content, antioxidant enzyme activities, TNS activity, and endogenous hormone levels between HY and LY.

Result HY trees began flowering 7 days earlier than LY, with a greater coefficient of variation in flower crown width. The pollen viability and stigma receptivity of both HY and LY increased at the onset of flowering, peaked on the third day of full bloom, and then declined. During the full-bloom stage, the pollen viability and stigma receptivity of HY were significantly higher than those of LY. In contrast, ROS levels in LY pistils were higher and antioxidant enzyme activities were lower. Additionally, during the full-bloom stage, polyamine content and TNS activity were significantly higher in LY pistils. From the early to late full-bloom stages (T2–T4), IAA, BR, and JA levels in HY generally increased, with IAA and BR peaking at T4 and JA reaching its maximum at T3. Additionally, CTK levels in HY were significantly higher than in LY at 0 d and 3 d of full bloom. Notably, elevated ABA levels in the styles of both HY and LY trees likely inhibited pollination and fertilization.

Conclusion There are significant differences in endogenous substances and reproductive traits (such as pollen viability and stigma receptivity) during the flowering period between HY and LY C. drupifera trees, which lead to differences in yield. The higher pollen viability and stigma receptivity in HY during the full-bloom stage indicate superior reproductive traits, conducive to subsequent fruit set. Conversely, the elevated ROS levels and reduced antioxidant enzyme activity in LY trees negatively impact pollen tube growth. The increased polyamine levels and TNS activity in LY trees during full bloom may play a role in mitigating self-incompatibility responses. These findings suggest that the application of exogenous ROS and ABA inhibitors, as well as polyamines, TNS, IAA, CTK, and JA during the flowering period may promote fruit set in C. drupifera.