Fig. 1.

Analysis of the activity of the MKKK18 promoter in transgenic plants expressing the ProMKKK18:GUS construct. (A) Schematic map of the MKKK18 promoter used for transformation and tissue-specific expression of MKKK18. (B) The ProMKKK18:GUS seedlings were germinated and grown on half-strength MS medium. Five-week-old plants were treated with either 0.1% methanol (mock) or 100 µM ABA. One representative of five independent lines is shown. (A) No changes in GUS activity after mock treatment. The scale bar represents 2,000 µm. (B–J) Plant samples 24 h after ABA treatment. GUS activity is visible in rosette leaves (B), flower buds and sepals (C), meristem tissues (D), pistils (E), anther filaments (F), lateral roots (G), trichomes (H), leaf guard cells (I) and hydathodes (J).