The capability to synthesize phytochelatins and the presence of constitutive and functional phytochelatin synthases are ancestral (plesiomorphic) characters for basal land plants.

Bryophytes, a paraphyletic group which includes liverworts, mosses, and hornworts, have been stated as land plants that under metal stress (particularly cadmium) do not synthesize metal-binding peptides such as phytochelatins. Moreover, very little information is available to date regarding phytochelatin synthesis in charophytes, postulated to be the direct ancestors of land plants, or in lycophytes, namely very basal tracheophytes. In this study, it was hypothesized that basal land plants and charophytes have the capability to produce phytochelatins and possess constitutive and functional phytochelatin synthases.