Rhizome Formation and Survival of Zizania latifolia (GRISEB.) STAPF. under Limited Oxygen Supply in Deep Water

Abstract

Based on the assumption that the oxygen supply to underground organs is by diffusion from aerial shoots to the lower boundary of Zizania latifolia (GRISEB.) STAPF, a model was constructed to determine whether buds from the presumed largest rhizomes can emerge in water 40 cm in depth such as occurs in the spring. A tank experiment was also carried out to determine the rates of bud emergence in spring from different-sized rhizomes transplanted the previous fall. Larger rhizomes had a higher rate of bud emergence. Seventy-six percent of buds from rhizomes larger than 40 cm³ in volume emerged. Dry weight of whole shoots and maximum dry weight of individual shoots that emerged from a rhizome were 8.1% and 2.1%, respectively, of the estimated initial dry weight of the rhizomes. About 24% of the dry weight of the rhizomes was lost during the winter. These results suggest that Z. latifolia grown in deep sediment where the oxygen concentration of the inner basal stem is 8.2% can produce rhizomes large enough for bud emergence in the spring when the water depth is 40 cm.