FIGURE 2 Characteristics and occurrence mechanisms of RCS in different cotton varieties after 15 days of drought stress. Statistical analysis of (A) the cortical senescence percentage, (B) cortical cell files and (C) the cortical lacunae area. DT type, Drought-tolerant type ”Guoxin 02”; DS type, Drought-sensitive type ”Ji 228”; NS, no-stress; DS, drought stress; C, varieties; D, drought. Error bars represent standard errors of the means. Different lowercase letters in the figure indicate significant differences between the same root segments from different cotton varieties under drought stress treatments (p ≤ 0.05).P >0.05, no significance (ns); P <0.01 significant difference (**).