Avocado flowers switch sex daily—now we know why
New work explains how avocado trees coordinate a complex reproductive strategy, switching every day between male and female
Avocado trees possess a unique reproductive strategy, switching between male and female roles every day. This fascinating dance between the flowers was first observed in 1927 by botanist A. B. Stout, but the mechanism behind it remained a mystery until recently. All avocado trees (Persea americana) are cosexual, containing both male and female organs within a single plant.
A-type trees display flowers receptive to pollen in the morning, transitioning to a male phase that produces pollen in the afternoon. Conversely, B-type trees operate on an opposite schedule, beginning as male flowers in the morning and becoming female in the afternoon. A new study in the Proceedings of the National Academy of Sciences USA, led by Jeffrey Groh of the University of California, Berkeley, has identified a single gene responsible for this sex-swapping behavior.
The protein produced by this gene activates a series of additional genes, orchestrating the flowers' opening and closing in a rhythmic pattern that supports the trees' reproductive process. This gene region exhibits a clear signal, almost glowing in the genetic landscape, thanks to advanced tools that have only recently become affordable and accessible.
While similar reproductive strategies exist in other flowering plants, the researchers found that avocado's unique method evolved independently multiple times. Genetic evidence suggests that avocados inherited this trait approximately 40 million years ago. The study highlights the remarkable ability of genetics to uncover ancient evolutionary secrets, reminding us that the phenomenon we observe today is just a small part of avocados' rich evolutionary history.
Written by urgent.news from Scientific American's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
