A group of scientists from Nagoya University in Japan have conducted a study using a specialized microscopic technique to observe the internal reproduction process of the Arabidopsis plant. Their findings, published in EMBO Reports, shed light on the mechanism behind how female flowers attract a single male counterpart, which could be crucial in optimizing seed production and improving agricultural breeding practices. Angiosperms, or flowering plants, have male and female reproductive organs, and when a pollen grain lands on the stigma of another flower, it initiates the formation of a pollen tube that allows sperm cells to reach the egg and central cells in the ovule for fertilization.
To gain a better understanding of this process, the researchers developed a unique microscopic technique using a two-photon microscope. Lead author Yoko Mizuta explained that the three-year effort involved delicate sample handling techniques and optimization of conditions to achieve deep imaging of flowers. With their technique, the team was able to observe the elongation of multiple pollen tubes within a living pistil and their attraction to female tissue, identifying a signal emitted by maternal tissue that guides pollen tubes to the site of fertilization in a one-to-one manner.
One-to-one pollen tube guidance is a critical process in plant reproduction and ensures successful fertilization by guiding individual pollen tubes to specific ovules. Mizuta and her colleagues also discovered a repulsion signal that is emitted to prevent multiple pollen tubes from fertilizing the same ovule. This signal directs rejected suitors to other unpaired ovules, along with a 45-minute blocking process to prevent multiple sperm from fertilizing the same ovule, revealing the complexity of the regulatory mechanism involved in pollen tube guidance.
The study highlighted the complexity of the one-to-one pollen tube guidance process, which involves various cells in both male and female plants to regulate successful fertilization and efficient seed production, especially in challenging environmental conditions. Mizuta underscored the significance of this mechanism in maximizing seed production, noting that plants have evolved a mechanism to control pollen tube behavior and ensure successful fertilization on dry land with limited suitors. The findings offer valuable insights into how plants reproduce and hold promise for enhancing agricultural breeding practices by increasing seed production and improving germination rates.
Overall, the research conducted by the team from Nagoya University provides valuable information on the mechanism behind plant reproduction. By using a specialized microscopic technique, the scientists were able to observe the intricate process of pollen tube guidance in angiosperms, shedding light on the signals that attract and repel pollen tubes for successful fertilization. These findings could have implications for optimizing seed production and improving agricultural breeding practices, ultimately benefiting food production and ensuring crop resilience in changing environmental conditions.