The leafs has long been considered an important organ for photosynthesis. Moderate leaf rolling in rice leads to erect leaf canopies and increased photosynthetic efficiency, improving stress response by reducing transpirational water loss and radiant heat absorption, thereby increasing grain yield. Therefore, moderate leaf rolling is an ideal trait for rice breeding. During screening of rice T-DNA insertion lines, a stable mutant showing abaxial rolled-leaf phenotype was obtained. Genetic analyses of heterozygous F₁ progeny showed that the mutant phenotype segregated in a 3:1 ratio of wild-type and mutant-like plants, so the leaf-rolling phenotype was caused by a single recessive mutation. Scanning electron microscopy revealed that stomatal phenotypes of mature leaves were changed and stoma number was increased in the mutant compared with wild type. In cross sectons taken from similar positions, the bulliform cell number and area were larger in the mutant than the wild type, which suggests that the outcurved leaf phenotype may be caused by the increase in bulliform cell number and size.