Effects of Complete Submergence on Growth, Survival and Recovery Growth of Alisma orientale (Samuel.) Juz.

Intense precipitations caused by global climate change will result in the occurrence of greater frequencies and longer durations of flooding, influencing the survival and yields of wetland plants. <i>Alisma orientale</i> (Samuel.) Juz., an important traditional medicine with edible scape and inflorescence, naturally grows in wetlands and artificially cultivates in paddy fields prone to flood in China. However, we lack understanding of the effect of complete submergence on <i>A</i>. <i>orientale</i>. Here, experiments with four durations of complete submergence including 5 days (ds), 10 ds, 15 ds and 20 ds followed by 20 ds recovery were performed. In the submergence experiments, the number of, length of and biomass of surviving leaves and the total biomass and new blade biomass were measured; in recovery experiments, number and length of surviving leaves were measured. <i>A. orientale</i> grew out longer new leaves during complete submergence, with a dramatic decline in the biomass of both the leaves and tubers as well as the total biomass at the ends of the submergence experiments. The <i>A. orientale</i> plants had a high survival rate after submergence. The duration of submergence did not influence the time for <i>A. orientale</i> needed to start regrowing. At the end of recovery period, the submerged <i>A. orientale</i> plants generated more leaves, had more surviving leaves, had shorter new leaves and a shorter total length of surviving leaves than the control plants. This study highlights that <i>A. orientale</i> plants can resist at least 20 ds of complete submergence caused by flooding and regrow rapidly after submergence and improves our understanding of the flooding tolerance mechanisms of <i>A. orientale</i> plants.