HO drives the transition from conchocelis to conchosporangia in the red alga with promotion facilitated by 1-Aminocyclopropane-1-carboxylic acid.

The Bangiales represent an ancient lineage within red algae that are characterized by a life history featuring a special transitional stage from diploid to haploid known as the conchosporangia stage. However, the regulatory mechanisms governing the initiation of this stage by changes in environmental conditions are not well understood. This study analyzed the changes in phytohormones and HO content during the development of conchosporangia.