3.2 The tissue appearance in normal anthers under confocal microscopy
Timeline was used to differentiate the locule of anthers spanning 32-day period from primordium to pollen grain. The appearance and division of locular cells were gritty, and key actions were listed in Figure2 and shown morphology of important cell types in confocal images ( Figure 2A-I). At least 60 anthers of each cell type were analyzed. The anthers smaller than 100 µm, no AR cells were seen; instead L2 layer in every locule was present arranged in a disorganized manner. After AR cells specification, ready for mitosis to produce the somatic (EN and SPL) and reproductive (PMC) cells. In 100 µm anthers, AR cells were clearly visible and present in the centre of locule (Figure 2A ). After the formation of AR cells, the somatic tissues become ready to pattern. According to our results AR cells differentiate to EN, SPL and PMC cells in 310 µm long anthers (Figure 2B ). According to linkage model, EN cells differentiate with SPL, which differentiate into ML and TA cells. Indeed, in 310 to 580 µm anthers, the four cells were differentiated clearly, which are named as the EPI, SPL, EN and PMC cells (Figure 2B-E ). At 580 µm, EN cells remain oval, while at 380 µm SPL showed round, and at 370 µm PMC cells has round like structures, indicative that these three have developed different identities (Figure 2C-E) . PMC cells undergoes meiosis and produce the tetrads cells (Tds) (Figure2F-G ). Additionally, the Tds cells generates the young MP cells (Figure 2H ). The MP raise larger and more spherical, and changed into PG. In the last stage, PG filled with the starch and released out by opening the stomium (Figure 2I ).