Figure 1.

Spore isolation and numbers of genes expressed throughout Arabidopsis male gametophyte development. (a) Purity of isolated spores in each developmental stage determined by microscopy: UNM, microspores; BCP, bicellular pollen; TCP, tricellular pollen; MPG, mature pollen. (b-e) DAPI-stained populations of developing spores: (b) microspores; (c) bicellular pollen; (d) tricellular pollen; and (e) mature pollen. (f) Total number of genes expressed in developing pollen and their distribution among three relative abundance classes. Gene-abundance classes were defined as follows: high (up to 10-fold less than the maximum signal), medium (10- to 100-fold less) and low (more than 100-fold less).