Figure 4.

ZIX Promoter Activities in Gametophytes and Early Seeds.

Prefertilization ovules or seeds at 1 to 3 DAP of ZIX:GUS lines from reciprocal crosses with wild-type plants were stained with GUS solution and imaged with DIC microscopy. cc, central cell; ec, egg cell; sy, synergids. Arrows with a star point to the early zygote ([F] and [G]); normal arrows point to the elongated zygote (H) or one-cell embryo ([I] and [N]). Bars = 4 µm in the inset in (A) and 20 µm in all others.

(A) Functional megaspore; inset: pollen.

(B) Two-nucleate embryo sac.

(C) Four-nucleate embryo sac.

(D) Eight-nucleate/seven-cell embryo sac.

(E) Four-cell embryo sac.

(F) to (J) Seeds from ZIX:GUS × wild-type crosses.

(K) to (O) Seeds from wild-type × ZIX:GUS crosses.

(F), (G), (K), and (L) Early zygote.

(H) and (M) Elongated zygote.

(I) and (N) One-cell embryo.

(J) and (O) Two-cell embryo.