Fig. 1.

Development of secondary aerenchyma and hypertrophic lenticels in soybean plants after approx. 5 weeks of flooding. The broken line on the stem indicates the water level at 3·5 cm above the soil surface. Secondary aerenchyma (white tissue) was developed in the stem and the adventitious roots, and hypertrophic lenticels were observed just above the water surface. Therefore, when water level was raised from 3·5 cm to 6 cm, the hypertrophic lenticels were completely submerged. Scale bar = 20 mm.