Japanese climbing ferns are able to engineer the sex of nearby ferns to ensure equal numbers of male and female plants.

The Japanese climbing fern (Lygodium japonicum) is a native Asian fern, and researchers have now discovered that mature female plants can cause nearby plants to turn into males, simply by emitting a chemical. This technique reduces the need to self-fertilise, which allows the species to maintain genetic diversity.

A new study by researchers at Nagoya University in Japan has showed that ferns communicate across generations to maintain a balanced sex ratio, ensuring efficient reproduction. 

As female ferns mature, they secrete a pheromone called gibberellin. At the same time, they also emit an organic compound belonging to the methyl ester chemical group, which modifies the biochemical pathway of the gibberellin molecule. The two substances are released onto the wet forest floor, and the altered pathway of the gibberellin makes it easier to absorb by budding ferns. These ferns then express the necessary genes to complete gibberellin production - causing them to develop male organs.

Gibberellins control plant growth and development, and in particular, play a role in stem growth. The researchers studying the pheromone emitted by female Japanese climbing ferns hope that a better understanding of how it works could help farmers to breed more efficient strains of crops. 

It is not yet known whether other ferns have the ability to change the sex of their neighbours, but Jody Banks, a plant geneticist from Purdue University in the US, who was not involved in the study, is hoping to use the research to identify sex selection genes in other ferns.

"We know much more about sex in animals than we do in plants," said Banks, in a press release. "This is really the first study to put a molecular face to it."

The findings are published in the journal Nature.

Source: Nature