Fig. 3. Histochemical detection of GUS activity in PpLFY1-GUS lines (A-L) and PpLFY-2-GUS lines (M-AB). (A,M) A young gametophore. (B,N) A gametophore with leaves. The apices of the main (arrow) and lateral shoots (arrowhead) are indicated. (C-F,O-R) A developing archegonium. GUS activity was detected in the egg cell (arrow) as well as in the archegonium tissue. (G,S) Antheridia. The tissue with GUS activity is the shoot apex. (H,T) A young sporophyte (bracket). (I,U-W) A young sporophyte isolated from an archegonium. (J) A young sporophyte with aberrant morphology. (K) An abnormal sporophyte with double sporangia. (L,X-AB) A developing sporophyte. The upper, middle, and lower parts differentiate into the sporangium (Sp), the seta (Se) and the foot (F), respectively (X). Scale bars: 50 µm in A,C-M, O-AB; 1 mm in B,N.