Figure 1.

Developmental arrest in pirl1, pirl9 pollen. (A) Alexander-stained dehisced pollen from a pirl1/PIRL1, pirl9 plant, segregating at 50% for the pirl1, pirl9 mutant phenotype. Purple stain indicates viable pollen; (B) Nomarski DIC microscopy of post-meiotic tetrads in a pirl1/PIRL1, pirl9 anther in which double mutant microspores are segregating but cannot be clearly identified; (C) A pirl1/PIRL1, pirl9 anther with mitotic stage pollen; arrows indicate developmentally arrested pollen; (D) A mature pirl1/PIRL1, pirl9 anther; arrows indicate shrunken inviable double mutants segregating within the pollen population. Scale bars = 20 µm