Fig. 1.

M. truncatula elongated petiolule 1 (elp1) mutant lacks motor organs. (A and B) Morphologies of trifoliate leaves of wild type (A) and the elp1-1 mutant (B). Arrows indicate pulvini in A and asterisks the equivalent positions in B. (C and D) Longitudinal sections of a pulvinus of WT (C) or the replacement organ of the elp1 mutant (D). (E and F) Cross sections of a pulvinus of WT (E) or the replacement organ of the elp1 mutant (F). (G–L) Scanning electron microscope images of a pulvinus of WT (G–I) or the replacement organ of the elp1 mutant (J–L) with different magnifications.