Drought‐Induced Oxidative Conditions in Rice Anthers Leading to a Programmed Cell Death and Pollen Abortion*

Male gametophyte development of eukaryotic plants in general and rice in particular is especially sensitive to drought. Water deficit during this stage inhibits microspore development resulting in male sterility. To elucidate the molecular mechanism of the phenomenon, a water deficit‐induced experiment was conducted during anther development. Microscopic observations of anther cross‐sections labelled with TdT‐mediated dUTP nick‐end labelling (TUNEL) indicated programmed cell death (PCD) signals after three consecutive days of water deficit. PCD is a biological process featured by the fragmentation of genomic DNA and plays an important role in plant reproduction. PCD is often concurrent with biochemical and physical changes in the cytoplasm, nucleus and plasma membrane of the cells. In this study, biochemical assays showed depletion of the adenosine triphosphate pool, increased concentration of hydrogen peroxide (ROS) and down‐regulation of antioxidant transcripts in anthers. We argue that the interplay between PCD and oxidative stress in anthers might be a cause of pollen sterility in drought‐stressed rice.