Carbon, nitrogen and phosphorus stoichiometry of two submerged macrophytes are more affected by plant species and organs than by light

Abstract

Context Submerged macrophytes develop great phenotypic plasticity responding to light stress. However, the light effects on carbon (C), nitrogen (N) and phosphorus (P) stoichiometry of submerged macrophytes are unknown. Aims To determine the stoichiometric response of Myriophyllum spicatum and Vallisneria natans to a light gradient. Methods We determined the C, N and P stoichiometry of two aquatic plants grown in pots subjected to an incident light gradient ranging from 100 to 17% of incident light. Key results The C, N and P stoichiometry of V. natans (except C:N of root) were not significantly different among the light treatments, whereas those of M. spicatum (except leaf element concentrations and root element ratios) showed significant differences across the light gradient. The analysis of variance results implied that the species, plant organs and their interactions explained more than 75% of total variance of all measured indices (except C). Conclusions The C, N and P stoichiometry of the two studied submerged macrophytes are more affected by plant organs and species than by light irradiance. Implication Although C, N and P stoichiometry of submerged macrophytes was little affected by light irradiance, whether the stoichiometry of submerged macrophytes is stable under other environmental factors should be focused on in future investigation.