Fig. 1. Elongation responses of mature plants of deepwater rice cultivars Habiganj Aman II (HA II) and Baisbish (BSB), and submergence- tolerant cultivar FR13A to partial and complete submergence, and relative expression levels of SK1, SK2, SUB1A-1, SD1, and GRF1 in the internodes of HA II, BSB, and FR13A. A, Plant length and total internode length of the main stem measured before and after treatment. Thirteen-week-old plants were either completely submerged (CS) or partially submerged (PS) for 7 d (n = 6). In the partial submergence test, the water depth was adjusted daily to maintain the top 10-20 cm of foliage above the water surface. Air-grown control (Air) plants were grown under non-submerged conditions during the same period. B, Relative expression levels of genes in the internodes of HA II, BSB, and FR13A were detected using qRT-PCR. 17S rRNA was used as the internal control for normalization. Data are Mean ± SE (n = 3). Different lowercase letters indicate significant differences (P < 0.05) by the Tukey’s HSD test.