Fig. 3.

Phellem and ‘stele’ areas (mm²) at maximum root diameter of 15 accessions of Melilotus siculus grown in nutrient solution for 7 d under control (aerated root zone), deoxygenated stagnant root zone, partial shoot submergence or full shoot submergence (the latter two treatments also with deoxygenated stagnant root zone). ‘Stele’ included phellogen and internal tissues such as the vascular cylinder. Plants were 28 d old when treatments were imposed. Values are means ± s.e. of four replicates. The significance of the main factors (‘accession’ and ‘treatment’) and the interaction of these two factors are shown in the P-values in the figure. Statistical analyses of these data are given in Tables 1 and 2.