Spatial And Temporal Characteristics Of Non-structural Carbohydrates Contents Of Phragmites Australis And Spartina Alterniflora At Chongming Dongtan Wetland

Dongtan wetlands, Shanghai, Chongming, played an important and unique ecological roles in maintaining the stability of the regional ecosystem. At present, the native plant species Phragmites australis and the exotic plant species Spartina alterniflora have become the two dominant species in Dongtan wetland vegetation, and intensively competed each other in the intertidal habitats. This paper studied the spatial and temporal characteristics of non-structural carbohydrates (NSC) contents of the different parts of P. australis and S. alterniflora, in order to further interpret and analyze the pattern of competition between P. australis and S. alterniflora populations, and the future trend of development, and to provide a theoretical basis for the scientific management of Dongtan wetland vegetation. The main results showed that:(1) NSC contents of P. australis were almost always higher than those of S. alterniflora at every growth stage, every tidal level and every parts of plants. The NSC contents in both species increased along with the decrease of tidal levels, especially for S. alterniflora, which might help to improve their salt tolerance.(2) NSC contents in both species increased from the early growth stage to rapid growth stage and to the end of growth stage.(3) NSC contents in leaves were higher than those in stems and roots in order in both species; the total NSC contents in S. alterniflora were lower than those in P. australis, but the proportions of NSC contents in underground parts of P. australis were lower than those in S. alterniflora. NSC contents of S. alterniflora at the stem base were less than those of P. australis, implying that the growth of roots and rhizomes, resistance ability to disturbance and basal tillering ability for S. alterniflora might be stronger than those of P. australis.(4) the proportions of NSC contents in underground parts of both species decreased along with the increase of tidal levels, showing the change of trend from NSC content dominance in underground parts to NSC content dominance in aboveground parts in the two species.(5) NSC contents of newborn rhizome of P. australis were almost always higher than old rhizome, the NSC contents decreased along with the increase of the rhizome’s growth time.