Fig. 3
From: How exposure to ALS-inhibiting gametocide tribenuron-methyl induces male sterility in rapeseed
Structure of anthers and pollen of TBM-treated plants. (A-H are stained with toluidine blue and the scale bar = 20 μm; I-P are transmission electron microscope images with scale bar = 1 μm.). a Normal microsporocyte mother cell. b Normal tetrad. c Uni-nucleate microspore. d Near-mature pollen with deep stain. e TBM-treated microsporocyte mother cells and tapetal cells are loosely arranged. f Malformed tetrad microspores. g TBM-treat tapetal cells disappear at the uni-nucleate stage. h Several pollen grains can be stained by toluidine blue, but most unviable pollen grains are deformed. i Normal tapetum full of elaioplasts and tapetosomes at the late uni-nucleate microspore stage. j Early microspore with exine. k Late uni-nucleate microspore. l Mature pollen with well-formed exine. m Tapetum is degraded at the uni-nucleate microspore stage. n Early microspore full of autophagic vacuoles. o Malformed microspore with undeveloped exine. p Unviable microspore loses cytoplasm, with undeveloped exine. Abbreviation: El, elaioplast; Ex, exine; M, microspore; MMC, microspore mother cell; Po, pollen grain. T, tapetum; Ta, tapetosome; Te, tetrad