Figure 2.

Younger aerial roots produced more mucilage and were categorized into three stages. (A) The diameter of aerial roots does not change during plant development, but the amount of mucilage produced does change. (B) Stage 1 roots are shorter and produce up to 1.5 mL of mucilage. In stage 2, roots still produce mucilage up to 0.5 mL, and in stage 3, the root cap starts to detach from the aerial root, and mucilage is no longer produced. Stage 4 has no visible root cap and does not produce mucilage. The 2 mL tube in the picture was 4 cm long. (C) The root tip of the aerial root produces more mucilage than the base of the root, and water is necessary to contact the aerial root to stimulate the secretion of mucilage.