Figure 3.

Effects of Blocking Auxin Transport on Auxin Reporter DR5:GUS Expression and on Stamen Development.

(A) to (C) GUS staining of DR5:GUS flower buds and severed anthers cultured in vitro.

(A) Severed anther at time 0. Staining is absent.

(B) Flower bud after 24 h of culture. Strong staining is observed in all anthers. Arrowheads indicate filaments of severed anthers.

(C) Severed anther after 24 h of culture. Strong staining is observed in the whole anther.

(D) to (F) Expression of the DR5:GUS reporter in flower buds treated with water (D) or 10 mM NPA ([E] and [F]).

(D) Water-treated DR5:GUS inflorescence showing GUS staining in anthers at stages 10 and 11. Numbers indicate flower developmental stages.

(E) NPA-treated DR5:GUS inflorescence showing GUS staining in anthers of stages late 10 and 11. Numbers indicate flower developmental stages.

(F) Detail of (E) NPA-treated DR5:GUS inflorescence at late stage 10: GUS signal is observed in the theca and in the tissues surrounding the theca (arrows).

(G) to (I) Histochemical analysis of anther transverse sections of DR5:GUS flower buds treated with water (G) or 100 μM NPA ([H] and [I]).

(G) Theca of a water-treated anther at late stage 10. GUS staining is observed in tapetum and middle layer cells, in the endothecium, and in microspores. Bar = 10 μm.

(H) Theca of an NPA-treated anther at late stage 10. GUS staining is observed in tapetum and middle layer cells, in the endothecium, and in microspores. Bar = 10 μm.

(I) NPA-treated anther at late stage 11. Intense GUS staining is observed in the theca, in microspores, and in the procambium. Bar = 30 μm.

(J) to (L) Phenotype of stamens in mature flowers from DR5:GUS inflorescences treated with water (J), 10 μM NPA (K), or 100 μM NPA (L).

(J) Water-treated flower at stage 13. All the anthers are dehiscent.

(K) Flower treated with 10 μM NPA at stage 13. One anther is still indehiscent (arrowhead).

(L) Flower treated with 100 μM NPA at stage 13. All anthers are indehiscent (arrowheads).

En, endothecium; ML, middle layer; Ms, microspores; P, procambium; T, tapetum; Th, theca.