The secretion and retraction processes of pollination drops of ancient Platycladus orientalis and their response to different pollen types

The secretion and retraction of PDs may be two mutually exclusive processes that cannot be considered together. The younger the tree was, the stronger the driving force of secretion, as demonstrated by the higher PD secretion rate, larger surface area, and greater duration. The older the tree was, the stronger the driving force of retraction, as demonstrated by the significantly higher retraction rate of PDs after pollination. Each process has its own advantages and disadvantages in terms of pollination efficiency, but the decrease in the PD secretion rate by ancient <i>P. orientalis</i> was significantly lower than the increase in the PD retraction rate. In summary, female cones of older <i>P. orientalis</i> exhibit a greater reproductive ability than those of younger <i>P. orientalis</i>.