Secretion efficiency of different moss signal peptides. Signal sequences of PpAP1, PpFLP, PpLTP, PpPME1, PpXTH1, PpCALP were fused to rhVEGF. Shown are the mean values of three independent experiments with three transfections each time (n = 9). Prior to calculation of averages, outliers were removed if the z-score was >1. RhVEGF concentration of the PpAP1-construct was set to 100%. Error bars indicate the absolute average deviation (AAD) of the three experiments. Control: untransfected Physcomitrella protoplasts.