Fig. 2: Tapetal cells in dcl5-1 plants are delayed or arrested in achieving binucleate status.

a Transmission electron microscopy (TEM) of a fertile dcl5-1//Dcl5 2.0 mm anther lobe. At this stage, the tapetal cells (TPM) are packed with dark staining materials, likely exine components later secreted onto haploid microspores. The middle layer (ML), endothecial (EN), and epidermal (EPI) cells are highly vacuolated. The orange boxes mark two binucleated tapetal cells in which both nuclei were visible (red dots). b TEM of a sterile dcl5-1 anther lobe at the same stage, demonstrating distended, pale-staining, and mononucleate tapetal cells. Two anthers as replicates from dcl5-1//Dcl5 and two anthers from dcl5-1 were used for TEM study. The other replicate is shown in Supplementary Fig. 8. c dcl5-1//Dcl5, and d dcl5-1: three-dimensional reconstructions of cleared, 2.5 mm anthers stained with the nuclear marker Syto13. Individual nuclei of mononucleate tapetal cells are marked in purple, and binucleated cells are marked in yellow. e Quantification of binucleated cells in dcl5-1, dcl5-1//Dcl5, and Dcl5//Dcl5 siblings at the meiotic I (1.5 mm) and meiotic II (2.5 mm) stages, in a family segregating 1:2:1. Statistics: two-tailed Student’s T-test. Three replicates were used for 1.5 mm anthers of each genotype; five replicates were used for 2.5 mm anthers of each genotype. Gray dots represent individual replicates (see Source Data File). Error bars indicate standard error of the mean (s.e.m.).