Mastering the maze – how plant sperm reach their mating partners

March 2023

  • Date: Mar 27, 2023
  • Time: 02:00 PM - 03:30 PM (Local Time Germany)
  • Speaker: Anja Geitmann
  • Location: Central Building
  • Room: Seminar Room
  • Host: Arun Sampathkumar


Double fertilization in plants involves the delivery of the sperm cells to the female gametophyte through an extension of the pollen grain, the pollen tube. To reach the female gametophyte, growing pollen tubes must penetrate various pistillar tissues and find their target, the ovule. Although the pollen tube must overcome the impedance of the pistillar tissues, the role of mechanical forces and physical guiding mechanisms in directing pollen tube growth is poorly understood. We used a variety of mechanical assays to quantify the pollen tube's invasive force and interrogate how it responds to mechanical triggers. We designed a microfluidic platform that allows us to challenge pollen tubes with structural features and tunable mechanical obstacles. We found that tubes from different species behave differently and discovered that the cell wall co mponents pectin and callose play distinct roles in the pollen tube's growth behavior. Sperm cell delivery and fertilization in plants appear to be controlled by a precisely regulated cell growth mechanism that endows the pollen tube with an extremely fast and precisely directed growth pattern.

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