Heat Shock Stress Causes Stage-specific Male Sterility in Arabidopsis thaliana

during flower development, floral organs such as sepals, petals, stamens, and carpels developed normally. However, the development of pollen inside the anther was disrupted in a stage-specific manner, with floral stage 9 primordia failing to produce any pollen grains. Morphological analyses suggested that heat shock causes a failure of separation of pollen mother cells followed by microspore differentiation and/or inhibition of male meiotic processes. Heat shock also caused sterility in floral stage 12 flowers but the sterility was due to the failure of pollen release from the pollen sacs.