FIGURE 1.

Rboh-dependent superoxide production during gametophyte development. Location of ${\mathrm{O}}_{\mathrm{2}}^{\mathrm{•-}}$ during the development of gametophytes. (A) Two selected stages of late anther development (tetrads and microspores) and anthers at the dehiscence stage. (B) Three selected female gametophyte development stages, including the pre-meiotic phase, functional megaspore formation and the fully developed embryo sac stage. The localization of H₂O₂ accumulation is also shown when necessary (for more detailed information, see text above). Recognized sources of superoxide are marked in black. Blue star: ${\mathrm{O}}_{\mathrm{2}}^{\mathrm{•-}}$; red star: H₂O₂; T, tetrads; M, microspore; Mp, mature pollen; Mmc, megaspore mother cell; Fm, functional megaspore; Dm, degenerating megaspore; Ac, antipodal cell; Cc, central cell; S, synergid; E, egg cell; Mi, micropyle.