In vivo reciprocal cross-pollination of mms21-1 to wild-type plants. (A-D) Pistils were fixed at 12 h after pollination, and pollen tube growth was examined by aniline blue staining, bars = 500 μm. The remaining pollinated pistils ripened into mature siliques in 14 d, and siliques were then dissected for examination of fertilized ovules. Arrows indicate the pollen tube front in the pistil. Asterisks designate unfertilized ovules in the silique. (E-H) In another set of reciprocal cross-pollinations, sizes of mature siliques, numbers of seeds per silique and percentage aborted seeds per silique were examined 14 d after pollination. Control flowers were allowed to self-pollinate (asterisks). Data are shown as mean ± SD. (E) Percentage of pollen tubes growing to the base of the pistil. Bars = 5 mm.