Fig. 2.

Time courses of rates of radial O₂ loss at the basal part (15 mm below the root–shoot junction) of short and long adventitious roots following transfer into an O₂-free medium with shoots in air, at 28 °C (short adventitious roots, n = 3; long adventitious roots, n = 4; mean ± s.e.). Plants were raised for 3–4 weeks in aerated nutrient solution, and then transferred for 48 h to O₂-free stagnant 0·1 % agar solution that contained 5 mm KCl and 0·5 mm CaSO₄. Short (65–90 mm) and long (105–130 mm) adventitious roots were used in experiments (lengths at commencement of treatment); after 48 h in the stagnant agar, root lengths were: short, 66–94 mm (growth rate 1·5 mm d⁻¹); long, 110–131 mm (growth rate 3·4 mm d⁻¹). *Significant difference between short and long adventitious roots (P < 0·05, two-sample t-test).