title: [Nitrogen accumulation and allocation in Calamagrostis angusifolia in different plant communities of Sanjiang Plain].
abstract: From May to October in 2004, the characteristics of nitrogen (N) accumulation and allocation in Calamagrostis angustifolia, the dominant species in the typical meadow and marsh meadow communities of Sanjiang Plain, were studied. The results showed that the total nitrogen (TN) content in the aboveground organs and litters of typical meadow C. angustifolia (TMC) and marsh meadow C. angustifolia (MMC) decreased during growth season, which could be described by exponential decay model (TN = Aexp (-t/B1) + B2, R2 > or = 0.94). The TN content in TMC and MMC roots fluctuated greatly, and a significant N accumulation period (15-30 d) was observed before the coming of growth midseason. The N accumulation amount and rate of different organs and litters had obvious seasonal changes, and their values of the aboveground organs were much higher for TMC than for MMC, while the values of the roots were in adverse. The N allocation ratio of different parts of TMC and MMC also had significant differences. Root was the important N storage, and the root N allocation ratio of TMC and MMC was (59.38 +/- 12.86)% and (84.58 +/- 3.38)%, respectively. Among the aboveground parts, leaf had the highest N allocation ratio, being (24.28 +/- 12.09)% for TMC and (8.18 +/- 3.32)% for MMC. The change patterns of the N allocation ratio of aboveground and underground parts were just in adverse, which reflected the osculation contact in N supplement aspect. The annual N absorption amount and maximum standing crop of TMC and MMC were 23.02, 36.30 g x m(-2), and 28.18, 51.43 g x m(-2), respectively. The N absorption coefficient and utilization coefficient of TMC were much higher than those of MMC (0.017 and 0.634 relative to 0.015 and 0.548, respectively), illustrating that TMC had higher capability of N absorption and utilization than MMC.
authors.affiliation: Yantai Institute of Coastal Zone Research for Sustainable Development, Chinese Academy of Sciences, Yantai 264003, Shandong, China. zhigaosun@yahoo.com.cn
authors.forename: Zhi-Gao
authors.initials: ZG
authors.lastname: Sun
authors.forename: Jing-Shuang
authors.initials: JS
authors.lastname: Liu
authors.forename: Jun-Bao
authors.initials: JB
authors.lastname: Yu
mesh_terms: D002681:China; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D006109:Poaceae / Q000145:classification / Q000378:metabolism*; D012621:Seasons
chemical_list: D009584:Nitrogen