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ORIGINAL RESEARCH article

Front. Plant Sci.

Sec. Plant Development and EvoDevo

Volume 16 - 2025 | doi: 10.3389/fpls.2025.1669052

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

Provisionally accepted
Wei  ZhouWei Zhou1Liyan  GongLiyan Gong1Xiaobing  WangXiaobing Wang2Nawen  LiNawen Li1Xin  ZhangXin Zhang3*Jianjun  LiuJianjun Liu3
  • 1Guilin University of Electronic Technology, Guilin, China
  • 2Xinxiang University, Xinxiang, China
  • 3Northwest A&F University, Yangling, China

The final, formatted version of the article will be published soon.

The pollination drop (PD) is an important ovular secretion that occurs during the pollination stage in gymnosperms. In this study, ancient Platycladus orientalis trees near the Mausoleum of the Yellow Emperor were selected to investigate the secretion and retraction processes of PDs and the response of PDs to different pollen types. In a natural setting, PDs were secreted in the early morning and retracted around noon, with the appearance time extending equally to both sides of 6 a.m., and there was a daily circadian rhythm of the variations. Similar changes were observed under in vitro conditions. Immediately after pollination, the PDs were retracted rapidly for a short time, after which the retraction rate gradually decreased for the next 20 min, and then remained almost unchanged, suggesting that there may be a comprehensive retraction mechanism for PDs. After pollination, the PD retraction rate decreased with decreasing pollen viability and botanical affinity, suggesting the presence of substances used for pollen identification, an identification mechanism and the presence of specific forms of identification or communication with pollen. The ability of the PDs of ancient P. orientalis trees to identify and respond to pollen increased with increasing tree age. 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 P. orientalis was significantly lower than the increase in the PD retraction rate. In summary, female cones of older P. orientalis exhibit a greater reproductive ability than those of younger P. orientalis.

Keywords: Pollination drop, Platycladus orientalis, Pollen, ancient gymnosperm, secretion, retraction

Received: 23 Jul 2025; Accepted: 14 Oct 2025.

Copyright: © 2025 Zhou, Gong, Wang, Li, Zhang and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Xin Zhang, xin.zhang@nwsuaf.edu.cn

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