Fig. 5.

Volume of ¹⁸O₂ transported from the stem to the roots with or without exposure of the aerenchyma to the ¹⁸O₂ gas in each treatment. See Fig. 2 for an illustration of the treatment conditions. Flood Ae-Open, aerenchyma and lenticels above the water; Flood Ae-Submerged, submerged aerenchyma and lenticels. Values are the mean (±s.e.) of four or five plants. Means in the shoot followed by the same upper-case letter and means in the root followed by the same lower-case letter do not differ significantly (P < 0·01, Tukey–Kramer's test).