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Transverse section of secondary roots of Genipa americana (A–D) and Guazuma ulmifolia (E–H). The red stars indicate enlarging air spaces in the root cortex of Amazonian (A,B,E,F) and Cerrado (C,D,G,H) plants kept well-watered (A,C,E,G) and after 30 days of complete submersion (B, D, F, H).
