Fig. 2.

ABA promotes radial expansion of rice primary root cortical cells in compacted soil. (A–D) Representative images of wild-type (WT) and mhz5-1 (ABA-deficient mutant) root tips (meristematic and elongation zones) showing cortical cells in (A, B) noncompacted soil (1.1 g cm⁻³ BD) as compared with (C, D) compacted soil (1.6 g cm⁻³ BD). Scale bars = 100 µm. (E) Boxplot showing the radial expansion of root cortical cells in wild-type and mhz5-1 root tips (elongation zone) in noncompacted and compacted soils. (F–I) Representative radial sections of wild-type and mhz5-1 root tips grown under control (F, G) and 10 µM ABA (H, I) treatments for 48 h. Scale bar = 154.5 µm. (J) Boxplot of wild-type and mhz5-1 root tips showing the radial expansion of root cortical cells after ABA treatment. All experiments were repeated three times. *** represents P value of ≤ 0.0001 calculated by Student’s t-test between noncompacted and compacted treatments (E) and between control and ABA treatments (J).