While it certainly is possible to apply pollen to flowers by hand, doing so throughout an entire orchard would be quite time- and labor-intensive.
With that in mind, researchers from the Japan Advanced Institute of Science and Technology previously experimented with using tiny drones to directly pollinate tulips. And although they did have some success, it was difficult to keep the aircraft from damaging the delicate flowers by bumping into them.
Inspired by watching his son blowing soap bubbles, lead scientist Eijiro Miyako more recently wondered if such bubbles might be a better way to go. Working with researcher Xi Yang, he proceeded to test the bubble-forming and pollen-carrying capabilities of five commercially available surfactants.
One of them, known as lauramidopropyl betain (A-20AB), proved to be particularly effective.
The scientists therefore proceeded to add pear pollen to a solution of 0.4-percent A-20AB – the pH of the water that made up the rest of the solution was optimized to support germination, plus beneficial compounds such as calcium were added.
When that liquid was subsequently loaded into a bubble gun and applied (in bubble form) to pear trees in an orchard, pollen was successfully delivered to the targeted flowers, ultimately resulting in the production of fruit.
Next, a GPS-guided autonomous drone was used to blow the bubbles onto artificial lilies, as the real plants weren’t in bloom at the time. Flying at a height of 2 meters (6.6 ft) and traveling at a speed of 2 meters per second, it had a 90-percent success rate of delivering pollen to the flowers.
There are some limitations to the technique, however, such as the fact that wind could blow the bubbles away, or rain could wash them off the flowers. Additionally, the efficiency needs to be improved, as most of the bubbles still end up missing the targeted flowers.
The research is described in a paper that was recently published in the journal iScience.