Heat shock stress causes stage-specific male sterility in Arabidopsis thaliana

Although heat shock response in plants has been extensively studied, there has been little investigation into the effect of heat shock on plant organ development. When heat shock was applied to Arabidopsis during flower devel opment, floral organs such as sepals, petals, stamens, and carpels develope d normally. However, the development of pollen inside the anther was disrup ted in a stage-specific manner, with floral stage 9 primordia failing to pr oduce any pollen grains. Morphological analyses suggested that heat shock c auses a failure of separation of pollen mother cells followed by microspore differentiation and/or inhibition of male meiotic processes. Heat shock al so caused sterility in floral stage 12 flowers but the sterility was due to the failure of pollen release from the pollen sacs.