Ecological relationships of wild rice, Zizania aquatica. 6. The effects of increases in water depth on vegetative and reproductive production

Abstract

Wild rice (Zizania aquatica L.) suspended in plastic buckets from specially designed rafts, was subjected to increases in water depth during the submerged-leaf, first floating-leaf, second floating-leaf, and the first aerial-leaf stages. The depth was increased from an initial depth of 45 cm by 0 (control), 15, 30, or 50 cm. With the exception of the 15-cm treatment, increases in water depth resulted in decreases in total and component (root, stem, leaf) dry weights and the number of tillers on each plant. Plant height increased as the depth increased. Similar reductions occurred in the number of inflorescences per plant, the number of pedicels per plant, and the dry weights of the inflorescences. In all cases, the 15-cm treatment had higher production values than the control. The final biomass was influenced by the depth treatment, not the phenological stage when the depth increased.