<i>rbohH rbohJ</i> mutant pollen display <i>anxur</i>-like phenotypes.

<p>(A) Quantification of pollen germination and PT rupture percentages (top histogram) and seed per siliques (bottom histogram) for WT, single, and double <i>rboh</i> as well as <i>anx1 anx2</i> mutant plants. Data are mean ± standard error of the mean (SEM) of three independent experiments with more than 150 pollen grains or ten siliques per genotype and experiment. (B) Representative overview images of WT and <i>rbohH rbohJ</i> pollen grown <i>in vitro</i> for 5 h. Up to 80% of germinated pollen from <i>rbohH rbohJ</i> ruptured with clear traces of cytoplasmic content that was released into the medium (top right), while the remaining germinated grains produce PTs that will burst later on (bottom right, arrowheads) as opposed to WT PTs that grow normally (bottom left). Scale bar = 50 µm. (C) Photographs of siliques from WT, <i>rbohH rbohJ</i>, and <i>anx1 anx2</i> plants. Scale bar = 500 µm. (D) Representative images of aniline blue staining of a WT pistil pollinated with WT pollen (left), a <i>rbohH rbohJ</i> pistil with WT pollen (middle), and a WT pistil with <i>rbohH rbohJ</i> pollen (right). Eighteen hours after manual pollination, WT PTs (left and middle panels) had grown through the entire pistil to reach the female gametophytes. In contrast, most of the <i>rbohH rbohJ</i> mutant PTs (right) were arrested in the transmitting tract. White arrows indicate the tip of the longest PT. Scale bar = 5 mm.