Endoreduplication Cycles during Hypocotyl Growth of Cabbage (Brassica oleracea L.) under Light and Dark Conditions

Cabbage (Brassica oleracea L.) seedlings pursue two contrasting morphogenetic patterns, depending on the light environment. In the light, cabbage seedlings show short hypocotyls and open, unfolded cotyledons. In darkness, seedlings have markedly elongated hypocotyls and folded cotyledons. Durig hypocotyl growth, a majority of cells goes through endoreduplication. In light-grown hypocotyls, up to three cycles of endoreduplication occur, whereas in darkness about 10% of the total cells undergo the fourth cycles of endoreduplication. In both light and dark conditions, two cycles of endoreduplication take place prior to any significant hypocotyl growth. In darkness, the fourth cycle is completed very early during hypocotyl growth. These results support the view that endoreduplication may be a developmental programs in cabbage plants.