Response of OsPR1 genes to wounding The fourth leaves were cut into 1 cm length sections for wounding, and floated on water for 0, 1, 6, and 24 h under light, and then the leaf pieces were homogenized for RNA extraction. Relative expression levels compared with that of the control actin gene are shown. The wound-upregulated and -downregulated genes are marked with forward or reverse arrowheads, respectively. Bars indicate mean ± SD