摘要
Purpose of the current study was to investigate the effects of constantly wet and dried-rewetted sediments on root functional traits of emerged macrophytes and their nutrients removal abilities.It is based on the hypothesis that root characteristics and nutrients removal abilities of plants will be altered in the course of sediment desiccation.Four emerged macrophytes including two fibrous-root plants(Canna indica and Acorus calamus)and two thick-root plants(Alocasia cucullata and Aglaonema commutatum)were investigated for their root functional traits and rhizoperformance in both wet and dried-rewetted sediments.Results showed that sediment desiccation followed by rewetting substantially altered the root functional traits(root surface area,radial oxygen loss,and root activity)of plants due to adverse changes in morphological characteristics(porosity,bulk density,particle density)of dried-rewetted sediments than by wet sediments.Consequently,limited plants growth and removal of nitrogen(N),phosphorus(P)and dissolved organic carbon(DOC)were recorded in driedrewetted sediments and their pore water than in wet sediments.Radial oxygen loss from plant roots correlated positively with root functional traits,plants growth,and removal of N,P and DOC from pore water and sediment in both sediment types.Among the macrophyte species,the fibrous-root plants having advantages root functional traits,greatly influenced the rhizospheric conditions(pH,dissolved oxygen and redox potential),and demonstrated higher N,P and DOC reduction from both sediment types.While,the thick-rooted plants with thick diameter roots(D>1 mm)and higher rhizome exhibited longer life-span in both sediment types.
基金
supported by grants from the National Natural Science Foundation of China(Grant Nos.51839011,51861125201 and 51679228)
the Special Foundation on Water Pollution Control and Treatment of China(No.2017ZX07204005)。
