Robinson, S. R.; Ashton, N. W.

Auxin sensing and polar auxin transport (PAT) are required for normal growth and development of stem internodes and leaves of gametophores of Physcomitrium (formerly Physcomitrella) patens. Auxin is required for the formation of leaf apical cells, and NPA-driven elevation of the intracellular auxin/cytokinin ratio stimulates bifurcation at the leaf margin. Auxin is implicated in the differentiation of the leaf midrib. Auxin sensing and PAT appear not to be needed for the transition of gametophore buds into leafy shoots.