Physcomitrium patens (Hedw.) Mitt. growing in the dark defaults to an auxin- and cytokinin-independent developmental programme.

Auxin and cytokinin partially restore Physcomitrium (formerly Physcomitrella ) patens gametophores that have developed in the dark to a form more typical of those grown in light. Auxin synthesis and/or transport in gametophores decrease with time spent in the dark. Auxin synthesis resumes in the apices of dark-grown gametophores upon their return to the light. Red light and to a lesser extent blue light are sufficient for this. The mas and GH3 promoters are both auxin-inducible but respond differentially to spatial cues.