Original paper

Effects of burial depth and water depth on sprouting of turions and early growth of Myriophyllum oguraense Miki subsp. yangtzense Wang

Zhan, Cun-wei; Wang, Dong; Huang, Xiao-feng; Zhou, Jie

Abstract

Sedimentation and water depth are important determinants of early growth and survivorship for aquatic macrophytes. Myriophyllum oguraense subsp. yangtzense Wang is a submerged macrophyte endemic to China and grows readily in shallow lakes of the lower Yangtze River basin. To clarify the ecology, turion emergence and biomass allocation were investigated by buring turions at 0, 2, 4, and 6 cm depths in plastic pots with unsterilized lake sediment under 0, 15, and 60 cm water depths. Emergence percentage was greatly affected by burial depth and water depth. Turion sprouting rate was highest at 0 cm burial depth, and decreased with increasing burial depth at each water depth. Total biomass, plant height, above-ground stem mass ratio and root mass ratio were significantly affected by both burial depth and water depth. With increasing water depth, total biomass, plant height, root mass ratio, above-ground stem mass ratio and leaf mass ratio decreased, while below-ground stem mass ratio generally increased with increasing burial depth. Our data suggest that both burial depth and water depth are important determinants for the sprouting of turions and early growth process of M. oguraense subsp. yangtzense. We therefore conclude that sediment accumulation and water-level fluctuation might disrupt the natural regeneration for turions of M. oguraense subsp. yangtzense, which in turn influences its abundance, distribution and population dynamics.

Keywords

burial depthearly growthmyriophyllum oguraense miki subsp. yangtzenseimmature plant emergencewater depth