A comparative study of developing air chambers in flat and gibbous fronds of Lemna gibba L.

Cross-sections were made of developing gibbous and flat fronds of Lemna gibba G3 which were emerging from the reproductive pocket of the mother plant. In the gibbous fronds the cells of the developing air chamber walls and peripheral walls were in a more active stage of division than in the flat fronds. Consequently, it was demonstrated that gibbosity is initiated in a young developing frond mainly as a result of enhanced cell division and the subsequent increase in the number of cells.