Fig. 2

Correlation between flower bud size and the stage of pollen development in tobacco Nicotianatabacum L. plant. Microspores and pollen were isolated from buds of different sizes, stained with DAPI, and viewed under a fluorescence microscope using the UV light channel and normal light to determine the developmental stages of pollen. a1-a5 Flowers of various sizes. a1 10-12 mm. a2 18-22 mm. a3 28–32 mm. a4 38–42 mm. a5 open flower. b1-b5 Pollen at different developmental stages visualized by light microscope. c1-c5 Pollen at different developmental stages visualized by UV. b1and c1 Unicellular microspores. b2, c2 Early bicellular pollen. b3, c3 Mid‐bicellular pollen. b4, c4 Nearly mature pollen. b5, c5 Fully mature pollen