Pollen development in wild type and jai1-1. Semi-thin cross-sections of anthers of wild type (a) and jai1-1
(b) stained with toluidine blue. The developmental stages are indicated by numbers. Note the high number of aborted pollen grains in jai1-1 (b 4). Pollen of jai1-1 appear premature in development as shown by typical features, such as occurrence of the big central vacuole (arrows in b1), presence of starch grains (b1 – b3) and the glassy state (b3) appearing first in wild type from stage 4 onwards. Additionally, premature degeneration of tapetum (arrow heads) is visible in anthers of jai1-1. Bars represent 20 μm in (a1-3) and (b1-3), and 50 μm in (a4) and (b4).