Figure 7

Differential features of embryo and suspensor-like cells from two developmental pathways induced at 18°C. a-f) Suspensor-like pathway: individual micrographs showing the embryo head (a-c) and the suspensor-like structure (d-f). g-i) Developmental pathway without suspensor: rounded multicellular embryos surrounded by the exine. a, d, g) Subcellular organization observed in semithin sections stained with toluidine blue. DIC images (b, e, h) and anti-auxin immunofluorescence (c, f, i) of the same structures. Exine remnants are pointed by arrows. Embryo cells of both pathways showed similar organization with dense cytoplasms (a, g), and high IAA immunofluorescence signal (b, c, h, i), while suspensor-like cells displayed numerous vacuoles surrounding the central nucleus (d), and low IAA signal (e, f.)