Fig. 5.

Percentage cortical aerenchyma (A), average cortical cell size (B), number of metaxylem vessels (C), and the median area of each metaxylem vessel (D) from anatomical sections from the field are presented. Dotted lines represent planting density with gaps between dots being proportional to differences in densities, with 20K, 40K, and 80K being 20 000, 40 000, and 80 000 plants ha^–1. Triangles are in low nitrogen (LN) and circles in high nitrogen (HN). Points represent the mean of the four varieties in that Era time period in the specific N and density combination, and vertical lines the standard error. Letters demonstrate groupings from Tukey HSD mean comparisons among Era time periods (no differences indicate an insignificant effect of Era period). Presence or absence of an asterisk next to a treatment in the key indicates whether a treatment effect is significant or not, respectively. (This figure is available in colour at JXB online.)