Effect of submergence on the growth and development of aerenchyma in the roots of maize seedlings

Oxygen deprivation under submergence induced an adaptive response in maize seedlings. The gaseous regime in the water remained almost unchanged around the leaves, but in the root zone, the rapid decrease in pO(2) was accompanied by an appropriate increase in pCO(2). The growth of the root system and shoots was retarded from the very beginning of submergence; root growth was more strongly inhibited than that of shoots. Porosity in the roots and stem base significantly decreased in the course of ail experiments. Cellulase activity was examined in adventitious roots after submergence for 24, 48, and 72 hours, and after recovery. Cellulase activity doubled and more than tripled after submergence for 24 and 48 hours, respectively, as compared with enzyme activity in the roots of nonsubmerged plants. The enhanced cellulase activity in submerged adventitious roots is closely related to the formation of aerenchyma. The adaptation of roots to submergence can occur only during a short period; a long-term submergence results in plant death.