Seasonal variation of nitrogen and phosphorus contents of Phragmites communis in Taipa-Coloane wetland in Macao

To probe into the growth pattern of Phragmites communis and its functions in wetland ecosystem, six times of determinations were carried out on the nitrogen (N) and phosphorous (P) contents of P. communis in Taipa-Coloane wetland in Macao. The results showed that the N and P contents of P. communis aboveground part and underground stem reached the maximum in autumn and winter, and the minimum in spring and summer. The maximum N content in leaf, middle part of aboveground stem, and underground stem was 37.5, 14.1 and 10.2 g·kg~ -1 , and the minimum N content was 28.0, 11.5 and 6.6 g·kg~ -1 ; while the maximum P content was 4.0, 2.0 and 0.9 g·kg~ -1 , and the minimum P content was 3.5, 1.6 and 0.8 g·kg~ -1 , respectively. No mater what the sampling seasons were, the N and P contents decreased in the sequence of leafaboveground stemunderground stem, and no N and P transfer was observed among different organs or parts of the plant.