Abstract
The study of rice lamina has long history and always correlates to that of plant hormone. Two plant hormones, brassinosteroid (BR) and auxin are well-known regulator of lamina joint (LJ) bending. In this work, we analyzed the regulation of LJ bending by BR and auxin using BR-deficient and -insensitive rice mutant.
In wild-type rice, the response to BR and auxin was highest 3.5 to 4 days after sowing, namely, after the second leaf appears and before it fully expands. In the 4-day-old LJ, the expression of BRI1, the BR receptor, was observed both the adaxial and abaxial sides of leaf however, in the 5-day-old LJ, it was restricted to the adaxial side. The elongation of LJ was enhanced solely by the cell elongation. Interestingly, in BRI1-deficient d61 mutant, the response to auxin in LJ was decreased while, in BR-deficient d2 of brd1, it was increased than in WT.
