Figure 6: TTP mutants share a common developmental syndrome.
From: A protein phosphatase 2A complex spatially controls plant cell division
(a) Scanning electron microscopy images of 3-day-old seedlings of wild type and ton1, fass (fass-13, strong allele; fass-14 and fass-15 weak alleles), pp2aa, and pp2ac mutants. (b) Cleavage pattern in wild-type embryos from the single-celled (1c) to the 16-celled stage embryo (16c). The first division of the apical cell of the embryo is longitudinal, whereas the basal cell divides by transverse divisions leading to the formation of the suspensor. The two-celled embryo then divides longitudinally again, perpendicularly to the previous plane. The four resulting cells then divide by transverse divisions, giving rise to the eight-celled embryo. The next round of division establishes the protoderm cell layer by an asymetric cleavage parallel to the surface, to form the 16-celled embryo. (c) Division plane defects in ton1, fass-5, pp2aa1, pp2aa1-a2, pp2aa1-a3, pp2ac3-c4 mutant embryos. Two representative embryos are shown for each genotype. Abnormal division plane positioning in mutants occurs both in the suspensor and in the embryo proper (arrows). Scale bars, 250 μm (a); 20 μm (b,c).
